db2 driver error but able to establish connection - jdbc

Question

I am trying to use C3P0 connection pools for IBM DB2 Version 10.5.5 Fix Pack 5 with Java 8 .
Initially, I was getting this error so I changed jar to db2jcc4.jar but I still get below error in console,
1350 [C3P0PooledConnectionPoolManager[identityToken->2x0fal9iui9mpmdj6im3|c2e1f26]-HelperThread-#1] INFO com.mchange.v2.c3p0.SQLWarnings – Origination unknown: [10228][11541][4.11.77] Security exceptions occurred while loading driver. ERRORCODE=4223, SQLSTATE=null
com.ibm.db2.jcc.am.SqlWarning: Origination unknown: [10228][11541][4.11.77] Security exceptions occurred while loading driver. ERRORCODE=4223, SQLSTATE=null
at com.ibm.db2.jcc.am.gd.b(gd.java:207)
at com.ibm.db2.jcc.am.gd.b(gd.java:258)
at com.ibm.db2.jcc.am.jb.a(jb.java:887)
at com.ibm.db2.jcc.am.lb.a(lb.java:574)
at com.ibm.db2.jcc.am.lb.<init>(lb.java:555)
at com.ibm.db2.jcc.t4.b.<init>(b.java:305)
at com.ibm.db2.jcc.DB2SimpleDataSource.getConnection(DB2SimpleDataSource.java:214)
at com.ibm.db2.jcc.DB2Driver.connect(DB2Driver.java:460)
at com.mchange.v2.c3p0.DriverManagerDataSource.getConnection(DriverManagerDataSource.java:175)
at com.mchange.v2.c3p0.WrapperConnectionPoolDataSource.getPooledConnection(WrapperConnectionPoolDataSource.java:220)
at com.mchange.v2.c3p0.WrapperConnectionPoolDataSource.getPooledConnection(WrapperConnectionPoolDataSource.java:206)
at com.mchange.v2.c3p0.impl.C3P0PooledConnectionPool$1PooledConnectionResourcePoolManager.acquireResource(C3P0PooledConnectionPool.java:203)
at com.mchange.v2.resourcepool.BasicResourcePool.doAcquire(BasicResourcePool.java:1138)
at com.mchange.v2.resourcepool.BasicResourcePool.doAcquireAndDecrementPendingAcquiresWithinLockOnSuccess(BasicResourcePool.java:1125)
at com.mchange.v2.resourcepool.BasicResourcePool.access$700(BasicResourcePool.java:44)
at com.mchange.v2.resourcepool.BasicResourcePool$ScatteredAcquireTask.run(BasicResourcePool.java:1870)
at com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread.run(ThreadPoolAsynchronousRunner.java:696)
Caused by: java.security.PrivilegedActionException: java.lang.ClassNotFoundException: sun.io.ByteToCharConverter
at java.security.AccessController.doPrivileged(Native Method)
at com.ibm.db2.jcc.am.jb.r(jb.java:873)
at com.ibm.db2.jcc.am.jb.<clinit>(jb.java:484)
at com.ibm.db2.jcc.DB2Driver.connect(DB2Driver.java:117)
... 9 more
Caused by: java.lang.ClassNotFoundException: sun.io.ByteToCharConverter
at java.net.URLClassLoader.findClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Unknown Source)
at com.ibm.db2.jcc.am.jg.run(jg.java:19)
... 13 more
1350 [C3P0PooledConnectionPoolManager[identityToken->2x0fal9iui9mpmdj6im3|c2e1f26]-HelperThread-#0] INFO com.mchange.v2.c3p0.SQLWarnings – Origination unknown: [10228][11541][4.11.77] Security exceptions occurred while loading driver. ERRORCODE=4223, SQLSTATE=null
com.ibm.db2.jcc.am.SqlWarning: Origination unknown: [10228][11541][4.11.77] Security exceptions occurred while loading driver. ERRORCODE=4223, SQLSTATE=null
at com.ibm.db2.jcc.am.gd.b(gd.java:207)
at com.ibm.db2.jcc.am.gd.b(gd.java:258)
at com.ibm.db2.jcc.am.jb.a(jb.java:887)
at com.ibm.db2.jcc.am.lb.a(lb.java:574)
at com.ibm.db2.jcc.am.lb.<init>(lb.java:555)
at com.ibm.db2.jcc.t4.b.<init>(b.java:305)
at com.ibm.db2.jcc.DB2SimpleDataSource.getConnection(DB2SimpleDataSource.java:214)
at com.ibm.db2.jcc.DB2Driver.connect(DB2Driver.java:460)
at com.mchange.v2.c3p0.DriverManagerDataSource.getConnection(DriverManagerDataSource.java:175)
at com.mchange.v2.c3p0.WrapperConnectionPoolDataSource.getPooledConnection(WrapperConnectionPoolDataSource.java:220)
at com.mchange.v2.c3p0.WrapperConnectionPoolDataSource.getPooledConnection(WrapperConnectionPoolDataSource.java:206)
at com.mchange.v2.c3p0.impl.C3P0PooledConnectionPool$1PooledConnectionResourcePoolManager.acquireResource(C3P0PooledConnectionPool.java:203)
at com.mchange.v2.resourcepool.BasicResourcePool.doAcquire(BasicResourcePool.java:1138)
at com.mchange.v2.resourcepool.BasicResourcePool.doAcquireAndDecrementPendingAcquiresWithinLockOnSuccess(BasicResourcePool.java:1125)
at com.mchange.v2.resourcepool.BasicResourcePool.access$700(BasicResourcePool.java:44)
at com.mchange.v2.resourcepool.BasicResourcePool$ScatteredAcquireTask.run(BasicResourcePool.java:1870)
at com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread.run(ThreadPoolAsynchronousRunner.java:696)
Caused by: java.security.PrivilegedActionException: java.lang.ClassNotFoundException: sun.io.ByteToCharConverter
at java.security.AccessController.doPrivileged(Native Method)
at com.ibm.db2.jcc.am.jb.r(jb.java:873)
at com.ibm.db2.jcc.am.jb.<clinit>(jb.java:484)
at com.ibm.db2.jcc.DB2Driver.connect(DB2Driver.java:117)
... 9 more
Caused by: java.lang.ClassNotFoundException: sun.io.ByteToCharConverter
at java.net.URLClassLoader.findClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Unknown Source)
at com.ibm.db2.jcc.am.jg.run(jg.java:19)
... 13 more
Even if this error is present in logs, my stand alone Java app is able to make connections to database and gets results i.e. SELECT query is executed successfully.
How to fix this confusion?

Answer 1

The stack traces you are seeing come from SqlWarning objects, which probably means they are not fatal or serious problems. The apparent problem java.lang.ClassNotFoundException: sun.io.ByteToCharConverter seems pretty strange. But since it is coming through as a warning rather than thrown as an Exception, the driver has probably recovered from the problem, which is why your application seems to work.
JDBC Connections are permitted to store a chain of SQLWarnings, which might arise from anything, but which most applications simply ignore. (Most JDBC programmers are unaware they even exist.)
c3p0 is extremely neurotic about periodically checking for Connection warnings, logging them, and then clearing them, so that users of Connections don't see warnings derived from prior clients' uses. The logging of warnings can be annoying, though, so if you want, it is easy to suppress it (or redirect it to a separate file, or whatever). c3p0 logs warnings to a special logger named com.mchange.v2.c3p0.SQLWarnings. In the configuration file for whatever logging library you use, you can suppress this output by setting that logger's level to WARNING or above.
(A bit confusingly SQLWarnings are logged at INFO not WARNING. Since they usually represent information about conditions already recovered from, which driver authors understand that most developers never see, they don't substantively rise to the level of WARNING. So filtering out messages from com.mchange.v2.c3p0.SQLWarnings at INFO and below is sufficient to quiet the warnings. If you'd like to see the responsible code, it is here.)