For environments other than DEV, can I use JRE instead of JDK for JBoss EAP 7 as recommanded by Red-Hat ?
JDK and JRE both will work. With JRE some monitoring tool like jconsole,jstack,jmap,jvisualvm..etc are not available. So normally Red Hat recommend to use JDK. If you dont want to use these monitoring tool then you can go with JRE.
It's recommended to JDK while developing or testing the project, as it will give you more options.
But JRE would work fine if don't want to use other supports like monitoring tools, maven etc is not needed.
Related
Intellij automatically generates read-only debug options that include dt_socket but we are using this ancient jvm that "may" only support dt_shmem on windows. Just want to know for sure that it will never work with the version of intellij we are using.
rtfm says https://www.ibm.com/docs/en/sdk-java-technology/8?topic=applications-debugging-java
Secondary followup question. Is it possible to run websphere 8.5.5.19 on the oracle or openjdk jvm in a non-production environment.
dt_socket works on Windows as well. The documentation is a bit misleading in that dt_shmem is only an option on Windows.
For the record, that probably isn't an ancient JVM in there unless it just hasn't been updated. If you updated the JDK when you updated WAS to 8.5.5.19, it would have a version of Eclipse OpenJ9 from about a year ago (and Eclipse OpenJ9 is single source across all JDK releases, so it includes all the same JVM goodies as in recent JDK releases).
When I was installing WAS, there was a prompt alerting me to use Java 8 by default. I aggreed, because back then it wasn't matter which version to use.
Time passed and now I have necessity to use Java 6 in one of my profiles, which is coming with the WAS by default. Since I aggreed to use newer Java, WAS working on Java 8 by default now. I searched in installation repository, but in IBM Installation Manager Java versions I need are greyed out and cannot be installed separately.
Is there a way to install Java 6 alongside Java 8 in WAS, so I could just switch between them in profiles' setting? I tried official repository for Java 6, but it is empty since IBM dropped it's support in April.
P.S. I tried to change variable JAVA_HOME in Websphere profile setting (as well as in system variables) to look at JDK 1.6 I installed separately, but then my profile refuses to start.
Java 6 is no longer supported, so the WAS Installation Manager has likely removed the option to use JDK 6. For WAS 8.5 you can use either Java 7 or Java 8.
This article talks more about Java 6 End of Support:
https://developer.ibm.com/wasdev/blog/2017/10/25/java-6-end-support/
I found two JDK in my Mac,
one is in the path:'/System/Library/Java/JavaVirtualMachines/1.6.0jdk'
another is in the path:'/Library/Java/JavaVirtualMachines/1.7.0jdk'
what's the different? why there are two?
The /System/Library/Java/JavaVirtualMachines/1.6.0jdk is the JDK that Apple used to distribute with their operating system. They have since stopped providing a JDK and have left it up to the owner of the Java platform, Oracle, to provide the latest JDK and /Library/Java/JavaVirtualMachines/1.7.0jdk is the JDK provided by Oracle.
The difference is simply the version and vendor (provider) of the JDK. It's perfectly fine to have multiple JDKs on your system.
Can somebody tell me where to find a java jdk 6?
I need to downgrade from 7 because I have some problems with java-7 on my mac. I installed the jdk 7 from oracle.
There is support for mac but there is nothing for lower then jdk7.
Any idea?
You can use "Java Preferences" to set the older jdk 6 to be your default JDK. Use "spotlight" to find Java Preferences panel.
This might be what you are looking for. http://support.apple.com/kb/HT5559?viewlocale=en_US
I am looking at Java/J2EE hosting options. I looked around and found AWS and more but Heroku seems to fit well for me. Especially because of the clarity and documentation.
But going through their docs, I came across the "Prerequisites" and it said that :
> Your application must run on the OpenJDK version 6, or 7 (8 is also available in beta).
Does it mean I cannot host my web-app which is compiled in Sun JDK 1.6?
Using : Sun Java 1.6, JSF-2, Spring, Hibernate, MySQL
I just want to know if my web-app with the above specifications can be hosted in Heroku.
Thanks,
Akshat
OpenJDK 6 is compatible with Sun JDK 1.6 so you should be fine. If that doesn't work for you can could bring your own JDK with you to Heroku.