TDengine database 3.0.1.7 jdbc connect error [duplicate] - jdbc

I'm getting a NoSuchMethodError error when running my Java program. What's wrong and how do I fix it?

Without any more information it is difficult to pinpoint the problem, but the root cause is that you most likely have compiled a class against a different version of the class that is missing a method, than the one you are using when running it.
Look at the stack trace ... If the exception appears when calling a method on an object in a library, you are most likely using separate versions of the library when compiling and running. Make sure you have the right version both places.
If the exception appears when calling a method on objects instantiated by classes you made, then your build process seems to be faulty. Make sure the class files that you are actually running are updated when you compile.

I was having your problem, and this is how I fixed it. The following steps are a working way to add a library. I had done the first two steps right, but I hadn't done the last one by dragging the ".jar" file direct from the file system into the "lib" folder on my eclipse project. Additionally, I had to remove the previous version of the library from both the build path and the "lib" folder.
Step 1 - Add .jar to build path
Step 2 - Associate sources and javadocs (optional)
Step 3 - Actually drag .jar file into "lib" folder (not optional)

Note that in the case of reflection, you get an NoSuchMethodException, while with non-reflective code, you get NoSuchMethodError. I tend to go looking in very different places when confronted with one versus the other.

If you have access to change the JVM parameters, adding verbose output should allow you to see what classes are being loaded from which JAR files.
java -verbose:class <other args>
When your program is run, the JVM should dump to standard out information such as:
...
[Loaded junit.framework.Assert from file:/C:/Program%20Files/junit3.8.2/junit.jar]
...

If using Maven or another framework, and you get this error almost randomly, try a clean install like...
clean install
This is especially likely to work if you wrote the object and you know it has the method.

This is usually caused when using a build system like Apache Ant that only compiles java files when the java file is newer than the class file. If a method signature changes and classes were using the old version things may not be compiled correctly. The usual fix is to do a full rebuild (usually "ant clean" then "ant").
Sometimes this can also be caused when compiling against one version of a library but running against a different version.

I had the same error:
Exception in thread "main" java.lang.NoSuchMethodError: com.fasterxml.jackson.core.JsonGenerator.writeStartObject(Ljava/lang/Object;)V
at com.fasterxml.jackson.databind.ser.BeanSerializer.serialize(BeanSerializer.java:151)
at com.fasterxml.jackson.databind.ser.DefaultSerializerProvider.serializeValue(DefaultSerializerProvider.java:292)
at com.fasterxml.jackson.databind.ObjectMapper._configAndWriteValue(ObjectMapper.java:3681)
at com.fasterxml.jackson.databind.ObjectMapper.writeValueAsString(ObjectMapper.java:3057)
To solve it I checked, firstly, Module Dependency Diagram (click in your POM the combination -> Ctrl+Alt+Shift+U or right click in your POM -> Maven -> Show dependencies) to understand where exactly was the conflict between libraries (Intelij IDEA). In my particular case, I had different versions of Jackson dependencies.
1) So, I added directly in my POM of the project explicitly the highest version - 2.8.7 of these two.
In properties:
<jackson.version>2.8.7</jackson.version>
And as dependency:
<dependency>
<groupId>com.fasterxml.jackson.core</groupId>
<artifactId>jackson-databind</artifactId>
<version>${jackson.version}</version>
</dependency>
2) But also it can be solved using Dependency Exclusions.
By the same principle as below in example:
<dependency>
<groupId>group-a</groupId>
<artifactId>artifact-a</artifactId>
<version>1.0</version>
<exclusions>
<exclusion>
<groupId>com.fasterxml.jackson.core</groupId>
<artifactId>jackson-databind</artifactId>
</exclusion>
</exclusions>
</dependency>
Dependency with unwanted version will be excluded from your project.

This can also be the result of using reflection. If you have code that reflects on a class and extracts a method by name (eg: with Class.getDeclaredMethod("someMethodName", .....)) then any time that method name changes, such as during a refactor, you will need to remember to update the parameters to the reflection method to match the new method signature, or the getDeclaredMethod call will throw a NoSuchMethodException.
If this is the reason, then the stack trace should show the point that the reflection method is invoked, and you'll just need to update the parameters to match the actual method signature.
In my experience, this comes up occasionally when unit testing private methods/fields, and using a TestUtilities class to extract fields for test verification. (Generally with legacy code that wasn't designed with unit testing in mind.)

If you are writing a webapp, ensure that you don't have conflicting versions of a jar in your container's global library directory and also in your app. You may not necessarily know which jar is being used by the classloader.
e.g.
tomcat/common/lib
mywebapp/WEB-INF/lib

For me it happened because I changed argument type in function, from Object a, to String a. I could resolve it with clean and build again

In my case I had a multi module project and scenario was like com.xyz.TestClass was in module A and as well as in module B and module A was dependent on module B. So while creating a assembly jar I think only one version of class was retained if that doesn't have the invoked method then I was getting NoSuchMethodError runtime exception, but compilation was fine.
Related : https://reflectoring.io/nosuchmethod/

Why anybody doesn't mention dependency conflicts? This common problem can be related to included dependency jars with different versions.
Detailed explanation and solution: https://dzone.com/articles/solving-dependency-conflicts-in-maven
Short answer;
Add this maven dependency;
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-enforcer-plugin</artifactId>
<version>3.0.0-M3</version>
<configuration>
<rules>
<dependencyConvergence />
</rules>
</configuration>
</plugin>
Then run this command;
mvn enforcer:enforce
Maybe this is the cause your the issue you faced.

It means the respective method is not present in the class:
If you are using jar then decompile and check if the respective version of jar have proper class.
Check if you have compiled proper class from your source.

I have just solved this error by restarting my Eclipse and run the applcation.
The reason for my case may because I replace my source files without closing my project or Eclipse.
Which caused different version of classes I was using.

Try this way: remove all .class files under your project directories (and, of course, all subdirectories). Rebuild.
Sometimes mvn clean (if you are using maven) does not clean .class files manually created by javac. And those old files contain old signatures, leading to NoSuchMethodError.

Just adding to existing answers. I was facing this issue with tomcat in eclipse. I had changed one class and did following steps,
Cleaned and built the project in eclpise
mvn clean install
Restarted tomcat
Still I was facing same error. Then I cleaned tomcat, cleaned tomcat working directory and restarted server and my issue is gone. Hope this helps someone

These problems are caused by the use of the same object at the same two classes.
Objects used does not contain new method has been added that the new object class contains.
ex:
filenotnull=/DayMoreConfig.conf
16-07-2015 05:02:10:ussdgw-1: Open TCP/IP connection to SMSC: 10.149.96.66 at 2775
16-07-2015 05:02:10:ussdgw-1: Bind request: (bindreq: (pdu: 0 9 0 [1]) 900 900 GEN 52 (addrrang: 0 0 2000) )
Exception in thread "main" java.lang.NoSuchMethodError: gateway.smpp.PDUEventListener.<init>(Lgateway/smpp/USSDClient;)V
at gateway.smpp.USSDClient.bind(USSDClient.java:139)
at gateway.USSDGW.initSmppConnection(USSDGW.java:274)
at gateway.USSDGW.<init>(USSDGW.java:184)
at com.vinaphone.app.ttn.USSDDayMore.main(USSDDayMore.java:40)
-bash-3.00$
These problems are caused by the concomitant 02 similar class (1 in src, 1 in jar file here is gateway.jar)

To answer the original question. According to java docs here:
"NoSuchMethodError" Thrown if an application tries to call a specified method of a class (either static or instance), and that class no longer has a definition of that method.
Normally, this error is caught by the compiler; this error can only occur at run time if the definition of a class has incompatibly changed.
If it happens in the run time, check the class containing the method is in class path.
Check if you have added new version of JAR and the method is compatible.

I fixed this problem in Eclipse by renaming a Junit test file.
In my Eclipse work space I have an App project and a Test project.
The Test project has the App project as a required project on the build path.
Started getting the NoSuchMethodError.
Then I realized the class in the Test project had the same name as the class in the App project.
App/
src/
com.example/
Projection.java
Test/
src/
com.example/
Projection.java
After renaming the Test to the correct name "ProjectionTest.java" the exception went away.

NoSuchMethodError : I have spend couple of hours fixing this issue, finally fixed it by just renaming package name , clean and build ... Try clean build first if it doesn't works try renaming the class name or package name and clean build...it should be fixed. Good luck.

I ran into a similar problem when I was changing method signatures in my application.
Cleaning and rebuilding my project resolved the "NoSuchMethodError".

Above answer explains very well ..just to add one thing
If you are using using eclipse use ctrl+shift+T and enter package structure of class (e.g. : gateway.smpp.PDUEventListener ), you will find all jars/projects where it's present. Remove unnecessary jars from classpath or add above in class path. Now it will pick up correct one.

I ran into similar issue.
Caused by: java.lang.NoSuchMethodError: com.abc.Employee.getEmpId()I
Finally I identified the root cause was changing the data type of variable.
Employee.java --> Contains the variable (EmpId) whose Data Type has been changed from int to String.
ReportGeneration.java --> Retrieves the value using the getter, getEmpId().
We are supposed to rebundle the jar by including only the modified classes. As there was no change in ReportGeneration.java I was only including the Employee.class in Jar file. I had to include the ReportGeneration.class file in the jar to solve the issue.

I've had the same problem. This is also caused when there is an ambiguity in classes. My program was trying to invoke a method which was present in two JAR files present in the same location / class path. Delete one JAR file or execute your code such that only one JAR file is used. Check that you are not using same JAR or different versions of the same JAR that contain the same class.
DISP_E_EXCEPTION [step] [] [Z-JAVA-105 Java exception java.lang.NoSuchMethodError(com.example.yourmethod)]

Most of the times java.lang.NoSuchMethodError is caught be compiler but sometimes it can occur at runtime. If this error occurs at runtime then the only reason could be the change in the class structure that made it incompatible.
Best Explanation: https://www.journaldev.com/14538/java-lang-nosuchmethoderror

I've encountered this error too.
My problem was that I've changed a method's signature, something like
void invest(Currency money){...}
into
void invest(Euro money){...}
This method was invoked from a context similar to
public static void main(String args[]) {
Bank myBank = new Bank();
Euro capital = new Euro();
myBank.invest(capital);
}
The compiler was silent with regard to warnings/ errors, as capital is both Currency as well as Euro.
The problem appeared due to the fact that I only compiled the class in which the method was defined - Bank, but not the class from which the method is being called from, which contains the main() method.
This issue is not something you might encounter too often, as most frequently the project is rebuilt mannually or a Build action is triggered automatically, instead of just compiling the one modified class.
My usecase was that I generated a .jar file which was to be used as a hotfix, that did not contain the App.class as this was not modified. It made sense to me not to include it as I kept the initial argument's base class trough inheritance.
The thing is, when you compile a class, the resulting bytecode is kind of static, in other words, it's a hard-reference.
The original disassembled bytecode (generated with the javap tool) looks like this:
#7 = Methodref #2.#22 // Bank.invest:(LCurrency;)V
After the ClassLoader loads the new compiled Bank.class, it will not find such a method, it appears as if it was removed and not changed, thus the named error.
Hope this helps.

The problem in my case was having two versions of the same library in the build path. The older version of the library didn't have the function, and newer one did.

I had a similar problem with my Gradle Project using Intelij.
I solved it by deleting the .gradle (see screenshot below) Package and rebuilding the Project.
.gradle Package

I had faced the same issue. I changed the return type of one method and ran the test code of that one class. That is when I faced this NoSuchMethodError. As a solution, I ran the maven builds on the entire repository once, before running the test code again. The issue got resolved in the next single test run.

One such instance where this error occurs:
I happened to make a silly mistake of accessing private static member variables in a non static method. Changing the method to static solved the problem.

Related

Spring 4 with maven build application is not deployed in tomcat 8 compiled using java 8 upgradation.Unable to resolve [duplicate]

I am getting a NoClassDefFoundError when I run my Java application. What is typically the cause of this?
While it's possible that this is due to a classpath mismatch between compile-time and run-time, it's not necessarily true.
It is important to keep two or three different exceptions straight in our head in this case:
java.lang.ClassNotFoundException This exception indicates that the class was not found on the classpath. This indicates that we were trying to load the class definition, and the class did not exist on the classpath.
java.lang.NoClassDefFoundError This exception indicates that the JVM looked in its internal class definition data structure for the definition of a class and did not find it. This is different than saying that it could not be loaded from the classpath. Usually this indicates that we previously attempted to load a class from the classpath, but it failed for some reason - now we're trying to use the class again (and thus need to load it, since it failed last time), but we're not even going to try to load it, because we failed loading it earlier (and reasonably suspect that we would fail again). The earlier failure could be a ClassNotFoundException or an ExceptionInInitializerError (indicating a failure in the static initialization block) or any number of other problems. The point is, a NoClassDefFoundError is not necessarily a classpath problem.
This is caused when there is a class file that your code depends on and it is present at compile time but not found at runtime. Look for differences in your build time and runtime classpaths.
Here is the code to illustrate java.lang.NoClassDefFoundError. Please see Jared's answer for detailed explanation.
NoClassDefFoundErrorDemo.java
public class NoClassDefFoundErrorDemo {
public static void main(String[] args) {
try {
// The following line would throw ExceptionInInitializerError
SimpleCalculator calculator1 = new SimpleCalculator();
} catch (Throwable t) {
System.out.println(t);
}
// The following line would cause NoClassDefFoundError
SimpleCalculator calculator2 = new SimpleCalculator();
}
}
SimpleCalculator.java
public class SimpleCalculator {
static int undefined = 1 / 0;
}
NoClassDefFoundError In Java
Definition:
Java Virtual Machine is not able to find a particular class at runtime which was available at compile time.
If a class was present during compile time but not available in java classpath during runtime.
Examples:
The class is not in Classpath, there is no sure shot way of knowing it but many times you can just have a look to print System.getproperty("java.classpath") and it will print the classpath from there you can at least get an idea of your actual runtime classpath.
A simple example of NoClassDefFoundError is class belongs to a missing JAR file or JAR was not added into classpath or sometimes jar's name has been changed by someone like in my case one of my colleagues has changed tibco.jar into tibco_v3.jar and the program is failing with java.lang.NoClassDefFoundError and I were wondering what's wrong.
Just try to run with explicitly -classpath option with the classpath you think will work and if it's working then it's a sure short sign that someone is overriding java classpath.
Permission issue on JAR file can also cause NoClassDefFoundError in Java.
Typo on XML Configuration can also cause NoClassDefFoundError in Java.
when your compiled class which is defined in a package, doesn’t present in the same package while loading like in the case of JApplet it will throw NoClassDefFoundError in Java.
Possible Solutions:
The class is not available in Java Classpath.
If you are working in J2EE environment than the visibility of Class among multiple Classloader can also cause java.lang.NoClassDefFoundError, see examples and scenario section for detailed discussion.
Check for java.lang.ExceptionInInitializerError in your log file. NoClassDefFoundError due to the failure of static initialization is quite common.
Because NoClassDefFoundError is a subclass of java.lang.LinkageError it can also come if one of it dependency like native library may not available.
Any start-up script is overriding Classpath environment variable.
You might be running your program using jar command and class was not defined in manifest file's ClassPath attribute.
Resources:
3 ways to solve NoClassDefFoundError
java.lang.NoClassDefFoundError Problem patterns
I have found that sometimes I get a NoClassDefFound error when code is compiled with an incompatible version of the class found at runtime. The specific instance I recall is with the apache axis library. There were actually 2 versions on my runtime classpath and it was picking up the out of date and incompatible version and not the correct one, causing a NoClassDefFound error. This was in a command line app where I was using a command similar to this.
set classpath=%classpath%;axis.jar
I was able to get it to pick up the proper version by using:
set classpath=axis.jar;%classpath%;
One interesting case in which you might see a lot of NoClassDefFoundErrors is when you:
throw a RuntimeException in the static block of your class Example
Intercept it (or if it just doesn't matter like it is thrown in a test case)
Try to create an instance of this class Example
static class Example {
static {
thisThrowsRuntimeException();
}
}
static class OuterClazz {
OuterClazz() {
try {
new Example();
} catch (Throwable ignored) { //simulating catching RuntimeException from static block
// DO NOT DO THIS IN PRODUCTION CODE, THIS IS JUST AN EXAMPLE in StackOverflow
}
new Example(); //this throws NoClassDefFoundError
}
}
NoClassDefError will be thrown accompanied with ExceptionInInitializerError from the static block RuntimeException.
This is especially important case when you see NoClassDefFoundErrors in your UNIT TESTS.
In a way you're "sharing" the static block execution between tests, but the initial ExceptionInInitializerError will be just in one test case. The first one that uses the problematic Example class. Other test cases that use the Example class will just throw NoClassDefFoundErrors.
This is the best solution I found so far.
Suppose we have a package called org.mypackage containing the classes:
HelloWorld (main class)
SupportClass
UtilClass
and the files defining this package are stored physically under the directory D:\myprogram (on Windows) or /home/user/myprogram (on Linux).
The file structure will look like this:
When we invoke Java, we specify the name of the application to run: org.mypackage.HelloWorld. However we must also tell Java where to look for the files and directories defining our package. So to launch the program, we have to use the following command:
I was using Spring Framework with Maven and solved this error in my project.
There was a runtime error in the class. I was reading a property as integer, but when it read the value from the property file, its value was double.
Spring did not give me a full stack trace of on which line the runtime failed.
It simply said NoClassDefFoundError. But when I executed it as a native Java application (taking it out of MVC), it gave ExceptionInInitializerError which was the true cause and which is how I traced the error.
#xli's answer gave me insight into what may be wrong in my code.
I get NoClassFoundError when classes loaded by the runtime class loader cannot access classes already loaded by the java rootloader. Because the different class loaders are in different security domains (according to java) the jvm won't allow classes already loaded by the rootloader to be resolved in the runtime loader address space.
Run your program with 'java -javaagent:tracer.jar [YOUR java ARGS]'
It produces output showing the loaded class, and the loader env that loaded the class. It's very helpful tracing why a class cannot be resolved.
// ClassLoaderTracer.java
// From: https://blogs.oracle.com/sundararajan/entry/tracing_class_loading_1_5
import java.lang.instrument.*;
import java.security.*;
// manifest.mf
// Premain-Class: ClassLoadTracer
// jar -cvfm tracer.jar manifest.mf ClassLoaderTracer.class
// java -javaagent:tracer.jar [...]
public class ClassLoadTracer
{
public static void premain(String agentArgs, Instrumentation inst)
{
final java.io.PrintStream out = System.out;
inst.addTransformer(new ClassFileTransformer() {
public byte[] transform(ClassLoader loader, String className, Class classBeingRedefined, ProtectionDomain protectionDomain, byte[] classfileBuffer) throws IllegalClassFormatException {
String pd = (null == protectionDomain) ? "null" : protectionDomain.getCodeSource().toString();
out.println(className + " loaded by " + loader + " at " + new java.util.Date() + " in " + pd);
// dump stack trace of the thread loading class
Thread.dumpStack();
// we just want the original .class bytes to be loaded!
// we are not instrumenting it...
return null;
}
});
}
}
The technique below helped me many times:
System.out.println(TheNoDefFoundClass.class.getProtectionDomain().getCodeSource().getLocation());
where the TheNoDefFoundClass is the class that might be "lost" due to a preference for an older version of the same library used by your program. This most frequently happens with the cases, when the client software is being deployed into a dominant container, armed with its own classloaders and tons of ancient versions of most popular libs.
Java ClassNotFoundException vs NoClassDefFoundError
[ClassLoader]
Static vs Dynamic class loading
Static(Implicit) class loading - result of reference, instantiation, or inheritance.
MyClass myClass = new MyClass();
Dynamic(Explicit) class loading is result of Class.forName(), loadClass(), findSystemClass()
MyClass myClass = (MyClass) Class.forName("MyClass").newInstance();
Every class has a ClassLoader which uses loadClass(String name); that is why
explicit class loader uses implicit class loader
NoClassDefFoundError is a part of explicit class loader. It is Error to guarantee that during compilation this class was presented but now (in run time) it is absent.
ClassNotFoundException is a part of implicit class loader. It is Exception to be elastic with scenarios where additionally it can be used - for example reflection.
In case you have generated-code (EMF, etc.) there can be too many static initialisers which consume all stack space.
See Stack Overflow question How to increase the Java stack size?.
Two different checkout copies of the same project
In my case, the problem was Eclipse's inability to differentiate between two different copies of the same project. I have one locked on trunk (SVN version control) and the other one working in one branch at a time. I tried out one change in the working copy as a JUnit test case, which included extracting a private inner class to be a public class on its own and while it was working, I open the other copy of the project to look around at some other part of the code that needed changes. At some point, the NoClassDefFoundError popped up complaining that the private inner class was not there; double-clicking in the stack trace brought me to the source file in the wrong project copy.
Closing the trunk copy of the project and running the test case again got rid of the problem.
I fixed my problem by disabling the preDexLibraries for all modules:
dexOptions {
preDexLibraries false
...
I got this error when I add Maven dependency of another module to my project, the issue was finally solved by add -Xss2m to my program's JVM option(It's one megabyte by default since JDK5.0). It's believed the program does not have enough stack to load class.
In my case I was getting this error due to a mismatch in the JDK versions. When I tried to run the application from Intelij it wasn't working but then running it from the command line worked. This is because Intelij was attempting to run it with the Java 11 JDK that was setup but on the command line it was running with the Java 8 JDK. After switching that setting under File > Project Structure > Project Settings > Project SDK, it worked for me.
Update [https://www.infoq.com/articles/single-file-execution-java11/]:
In Java SE 11, you get the option to launch a single source code file
directly, without intermediate compilation. Just for your convenience,
so that newbies like you don't have to run javac + java (of course,
leaving them confused why that is).
NoClassDefFoundError can also occur when a static initializer tries to load a resource bundle that is not available in runtime, for example a properties file that the affected class tries to load from the META-INF directory, but isn’t there. If you don’t catch NoClassDefFoundError, sometimes you won’t be able to see the full stack trace; to overcome this you can temporarily use a catch clause for Throwable:
try {
// Statement(s) that cause(s) the affected class to be loaded
} catch (Throwable t) {
Logger.getLogger("<logger-name>").info("Loading my class went wrong", t);
}
I was getting NoClassDefFoundError while trying to deploy application on Tomcat/JBOSS servers. I played with different dependencies to resolve the issue, but kept getting the same error. Marked all javax.* dependencies as provided in pom.xml, And war literally had no Dependency in it. Still the issue kept popping up.
Finally realized that src/main/webapps/WEB-INF/classes had classes folder which was getting copied into my war, so instead of compiled classes, this classes were getting copied, hence no dependency change was resolving the issue.
Hence be careful if any previously compiled data is getting copied, After deleting classes folder and fresh compilation, It worked!..
If someone comes here because of java.lang.NoClassDefFoundError: org/apache/log4j/Logger error, in my case it was produced because I used log4j 2 (but I didn't add all the files that come with it), and some dependency library used log4j 1. The solution was to add the Log4j 1.x bridge: the jar log4j-1.2-api-<version>.jar which comes with log4j 2. More info in the log4j 2 migration.
This error can be caused by unchecked Java version requirements.
In my case I was able to resolve this error, while building a high-profile open-source project, by switching from Java 9 to Java 8 using SDKMAN!.
sdk list java
sdk install java 8u152-zulu
sdk use java 8u152-zulu
Then doing a clean install as described below.
When using Maven as your build tool, it is sometimes helpful -- and usually gratifying, to do a clean 'install' build with testing disabled.
mvn clean install -DskipTests
Now that everything has been built and installed, you can go ahead and run the tests.
mvn test
I got NoClassDefFound errors when I didn't export a class on the "Order and Export" tab in the Java Build Path of my project. Make sure to put a checkmark in the "Order and Export" tab of any dependencies you add to the project's build path. See Eclipse warning: XXXXXXXXXXX.jar will not be exported or published. Runtime ClassNotFoundExceptions may result.
It could also be because you copy the code file from an IDE with a certain package name and you want to try to run it using terminal. You will have to remove the package name from the code first.
This happens to me.
Everyone talks here about some Java configuration stuff, JVM problems etc., in my case the error was not related to these topics at all and had a very trivial and easy to solve reason: I had a wrong annotation at my endpoint in my Controller (Spring Boot application).
I have had an interesting issue wiht NoClassDefFoundError in JavaEE working with Liberty server. I was using IMS resource adapters and my server.xml had already resource adapter for imsudbJXA.rar.
When I added new adapter for imsudbXA.rar, I would start getting this error for instance objects for DLIException, IMSConnectionSpec or SQLInteractionSpec.
I could not figure why but I resolved it by creating new server.xml for my work using only imsudbXA.rar. I am sure using multiple resource adapters in server.xml is fine, I just had no time to look into that.
I had this error but could not figure out the solution based on this thread but solved it myself.
For my problem I was compiling this code:
package valentines;
import java.math.BigInteger;
import java.util.ArrayList;
public class StudentSolver {
public static ArrayList<Boolean> solve(ArrayList<ArrayList<BigInteger>> problems) {
//DOING WORK HERE
}
public static void main(String[] args){
//TESTING SOLVE FUNCTION
}
}
I was then compiling this code in a folder structure that was like /ProjectName/valentines
Compiling it worked fine but trying to execute: java StudentSolver
I was getting the NoClassDefError.
To fix this I simply removed: package valentines;
I'm not very well versed in java packages and such but this how I fixed my error so sorry if this was already answered by someone else but I couldn't interpret it to my problem.
My solution to this was to "avail" the classpath contents for the specific classes that were missing. In my case, I had 2 dependencies, and though I was able to compile successfully using javac ..., I was not able to run the resulting class file using java ..., because a Dynamic class in the BouncyCastle jar could not be loaded at runtime.
javac --classpath "ext/commons-io-2.11.0;ext/bc-fips-1.0.2.3" hello.java
So at compile time and by runtime, the JVM is aware of where to fetch Apache Commons and BouncyCastle dependencies, however, when running this, I got
Error: Unable to initialize main class hello
Caused by: java.lang.NoClassDefFoundError:
org/bouncycastle/jcajce/provider/BouncyCastleFipsProvider
And I therefore manually created a new folder named ext at the same location, as per the classpath, where I then placed the BouncyCastle jar to ensure it would be found at runtime. You can place the jar relative to the class file or the jar file as long as the resulting manifest has the location of the jar specified. Note I only need to avail the one jar containing the missing class file.
Java was unable to find the class A in runtime.
Class A was in maven project ArtClient from a different workspace.
So I imported ArtClient to my Eclipse project.
Two of my projects was using ArtClient as dependency.
I changed library reference to project reference for these ones (Build Path -> Configure Build Path).
And the problem gone away.
I had the same problem, and I was stock for many hours.
I found the solution. In my case, there was the static method defined due to that. The JVM can not create the another object of that class.
For example,
private static HttpHost proxy = new HttpHost(proxyHost, Integer.valueOf(proxyPort), "http");
I got this message after removing two files from the SRC library, and when I brought them back I kept seeing this error message.
My solution was: Restart Eclipse. Since then I haven't seen this message again :-)

Error with running Drools - how should I debug?

I have a Drools file within a Java program (in this case a variation of Optaplanner), which I am building on Netbeans 8. When I run the program I get an error message:
Exception in thread "main" java.lang.IllegalArgumentException: The scoreDrl (taskassignment/solver/taskAssignmentScoreRules.drl) does not exist as a classpath resource.
at org.optaplanner.core.config.score.director.ScoreDirectorFactoryConfig.buildKieBase(ScoreDirectorFactoryConfig.java:304)
at org.optaplanner.core.config.score.director.ScoreDirectorFactoryConfig.buildDroolsScoreDirectorFactory(ScoreDirectorFactoryConfig.java:279)
at org.optaplanner.core.config.score.director.ScoreDirectorFactoryConfig.buildScoreDirectorFactory(ScoreDirectorFactoryConfig.java:186)
at org.optaplanner.core.config.score.director.ScoreDirectorFactoryConfig.buildScoreDirectorFactory(ScoreDirectorFactoryConfig.java:174)
at org.optaplanner.core.config.solver.SolverConfig.buildSolver(SolverConfig.java:145)
at org.optaplanner.core.config.solver.XmlSolverFactory.buildSolver(XmlSolverFactory.java:101)
at taskassignment.app.TaskAssignmentHelloWorld.main(TaskAssignmentHelloWorld.java:32)
Having Googled the error mesage, it seems the does not exist as a classpath resource is thrown from Optaplanner when there is a mistake in the drools code.
My question is, with no further information on where the error(s) is/are in the drools file, what is a good way of debugging this piece of code? Are there any plugins that could help me narrow down where the problem is like Netbeans normally would with Java?
Here is my Drools code for good measure:
package taskassignment.solver;
dialect "java"
import org.optaplanner.core.api.score.buildin.hardsoft.HardSoftScoreHolder;
import taskassignment.domain.TaskAssignment;
import taskassignment.domain.Task;
import taskassignment.domain.Dev;
global HardSoftScoreHolder scoreHolder;
// ############################################################################
// Hard constraints
// ############################################################################
rule "DevCanOnlyDoOneTask"
when
$T1:Task
$T2:Task
$D:Dev
(($T1.getAssignedDev()=$D)&&($T2.getAssignedDev()=$D)&&(($T2.getAllottedStartTime()<=$T1.getAllottedStartTime())&&($T1.getAllottedStartTime()<$T2.getAllottedStartTime()+$T2.getDuration()))||(($T1.getAllottedStartTime()<=$T2.getAllottedStartTime())&&($T2.getAllottedStartTime()<$T1.getAllottedStartTime()+$T1.getDuration()))
then
scoreHolder.addHardConstraintMatch(kcontext,-1000);
end
// ############################################################################
// Soft constraints
// ############################################################################
rule "MaximiseEarliestFinishTime"
when
$TA: TaskAssignment
$EFT: $TA.getEFT()
then
scoreHolder.addSoftConstraintMatch(kcontext,+$EFT);
Thanks guys
When there is a mistake in the drools (DRL) code, it throws a different exception, coming from drools and stating on which line in the DRL the error message is.
The message
The scoreDrl (taskassignment/solver/taskAssignmentScoreRules.drl) does not exist as a classpath resource.
means that you've configured this in your solver config
<scoreDrl>taskassignment/solver/taskAssignmentScoreRules.drl</scoreDrl>
and that's not a valid classpath resource location.
In a typical project with a maven directory structure, classpath resources are located under src/main/resources.
Pitfall: In 6.0, OptaPlanner uses Class.getResource(String) to find it. In 6.1.0.Beta3+, OptaPlanner uses ClassLoader.getResource(String) to find it. This means that currently in 6.0 it needs to start with a / and in 6.1 it must not start with a /.
So if you have a resource file in your project sources like this (presuming you're using the maven directory structure):
PROJECT_DIR/src/main/resources/taskassignment/solver/taskAssignmentScoreRules.drl
In 6.0 you'd need to configure:
<scoreDrl>/taskassignment/solver/taskAssignmentScoreRules.drl</scoreDrl>
And in 6.1 you'd need to configure:
<scoreDrl>taskassignment/solver/taskAssignmentScoreRules.drl</scoreDrl>
Note: you probably want to follow java conventions and use reverse url namespace. So instead of taskassignment/solver/..., I 'd use com/mycompany/taskassignment/solver/....

Which JAR file contains the JsonProcessingException class?

When I try to use Jackson 2.1.1 with the following jar files (in Spring 3.2.2),
jackson-core-2.1.1.jar
jackson-annotations-2.1.1.jar
jackson-databind-2.1.1.jar
I get the following exception.
java.lang.ClassNotFoundException:
org.codehaus.jackson.JsonProcessingException
So I think, the class JsonProcessingException is contained by the jackson-core-asl-2.1.1.jar file (I'm not quite sure though) but I cannot see this file in the download. So where to get this file to resolve that exception?
jackson-all-1.9.8.jar contains necessary classes including the class org.codehaus.jackson.JsonProcessingException and JSON also works fine but I'm not sure this is perfectly compatible as I'm using classes from Jackson 2.1.1 for object mapping. Therefore I'm looking for the jackson-core-asl-2.1.1.jar file but I can't see such a JAR file. I can only see 1.x.x versions here.
In version 2.1.2, that class is called com.fasterxml.jackson.core.JsonProcessingException, and it's in the jackson-core jar. Jackson changed its packaging for version 2.0, along with numerous other things.
It seems you have some code that was written against an older version of Jackson, and is trying to load the class under an old name. You will need to either update this code, or use an old version of Jackson.
Use jackson-all-1.9.9 jar instead of the later versions(2.x.x.) of jackson-core, jackson-annotations and jackson-databind. Here is the link.

Spring namespaces and placeholder in springs.schemas

Spring-namespaces allows you to define your own structure how spring beans could be configured. Very cool.
I have to use a 3rd party software (Assentis Docbase) which defines in its spring.schemas the following (example below simplified)
http\://com.apress.prospring2/ch07/custom.xsd=custDir:/custom.xsd
Meaning: If user defines in its spring-xml with schema-location: "http://com.apress.prospring2/ch07/custom.xsd" spring will validate this file against custom.xsd.
custDir is a directory OUTSIDE the provided jar. Does anyone have an idea how I can set this custDir to point to a valid path during junit test? I already tried -DcustDir=/pathToXsd/ but it did not work.
If I remove custDir than everything works as expected, but I can not remove it from provided spring.schemas since it is 3rd party software.
Maybe this is an issue how property-files are handled in java but I have no idea.
You may be able to "override" this entry by providing your own custom spring.schemas file with the same entry but with a location to your custom xsd file. The catch is that this is highly dependent on the order in which the spring.schemas are loaded up, but could be worth a try.
Since custDir is not a place holder, you cannot replace it the way you are doing it, I am surprised that the third party schema location is outside of the classpath.
The syntax of spring.schemas I provided in my question is a properitary definition of 3.rd party software. They implemented there own EntityResolver which manually reacts on "custDir:" and starts some magic algorithm. So I came to the following workaround.
You have to create your own my_spring.schemas which must be live in META-INF/. Than you have to make sure that spring loads my_spring.schemas and NOT spring.schemas.
I achieved it with implementing my own TestingContext which is a subclass of ClassPathXmlApplicationContext. In TestingContext I overwrote method protected void loadBeanDefinitions(DefaultListableBeanFactory beanFactory) throws IOException and filled it with implementation from org.springframework.context.support.AbstractXmlApplicationContext. The only change I made was to line beanDefinitionReader.setEntityResolver(new ResourceEntityResolver(this)) to beanDefinitionReader.setEntityResolver(new PluggableSchemaResolver(getClassLoader(), "META-INF/my_spring.schemas). And voila if I use TestingContext my own my_spring.schemas is loaded.
Drawback with this solution is that you have to provide all xsd in your jar because the default name, where spring looks up definitions has been changed.

XSLT ClassCastException in WebSphere when Spring tries to create an AnnotationMethodHandlerAdapter

When starting WebSphere, I get this exception:
Could not instantiate bean class [org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter]:
Constructor threw exception; nested exception is java.lang.ClassCastException:
com.ibm.xtq.xslt.jaxp.compiler.TransformerFactoryImpl incompatible with
javax.xml.transform.TransformerFactory
Caused by: java.lang.ClassCastException: com.ibm.xtq.xslt.jaxp.compiler.TransformerFactoryImpl
incompatible with javax.xml.transform.TransformerFactory
at javax.xml.transform.TransformerFactory.newInstance(Unknown Source)
at org.springframework.http.converter.xml.AbstractXmlHttpMessageConverter.<init>(AbstractXmlHttpMessageConverter.java:47)
at org.springframework.http.converter.xml.SourceHttpMessageConverter.<init>(SourceHttpMessageConverter.java:45)
at org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter.<init>(AnnotationMethodHandlerAdapter.java:197)
This doesn't seem have any impact on any beans in my applicationContext.xml but it's still odd. For me, this looks as if IBM classes are leaking into my application.
How can I fix this? I already set the option "Access to internal server classes" to "Restrict".
It was indeed a class-loading issue, however this cannot be solved by changing class-loader settings.
The problem was that the xml-apis and javax.xml jars were being imported over some maven dependencies.
Since we already set the class loader policies for the application to PARENT_LAST, the javax.xml.transform.TransformerFactory was being loaded from the WebApp-Class loader from our jar files.
However its implementation 'com.ibm.xtq.xslt.jaxp.compiler.TransformerFactoryImpl' was coming from the server class loader, this one was linked to the javax.xml.transform.TransformerFactory provided by the JDK/JRE.
Since the classes were loaded from different sources a ClassCastException was thrown.
Removing all dependencies to xml-apis / xerces / javax.xml jars solved the problem.
Since these APIs are now part of the JDK they no longer need to be imported.
... and if you wonder why I know so much about this issue: I work together with Aaron. ;)
I can't speak for Restrict as I have no personal experience with it,But I think the problem is more to do with IBM Class Loader. The class you are referring to is part of IBM Java implementation of TransformerFactory, I think you can try one of the following to solve this issue on hand
Either change the server class loader policy to PARENT_LAST (This way class loader will find the class from application's local class path, before going to up the chain all the way to java run time)
The other option would be look at the jaxp.properties file, I think it is located in (was_root\java\jre\lib), I only read about this option never actually used it
Why do you say IBM classes are leaking into your application?
The TransformerFactory is asked to create a newInstance. It follows a sequence of steps to determine which TransformerFactory to use. If none of the config is specified, it simply chooses to use the default factory.
Here is the javadoc for TransformerFactory:
http://download.oracle.com/javase/1.5.0/docs/api/javax/xml/transform/TransformerFactory.html#newInstance()
What is the OS ? Is that AIX?
http://www.ibm.com/developerworks/java/jdk/aix/j664/sdkguide.aix64.html
Looking at this doc (link above) for AIX it tells me that this is the default Impl:
javax.xml.transform.TransformerFactory
Selects the XSLT processor. Possible values are:
com.ibm.xtq.xslt.jaxp.compiler.TransformerFactoryImpl
Use the XL TXE-J compiler. This value is the default.
Post back additional information so that we can try and troubleshoot this.
HTH
Manglu

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