CODEWITHSUNDEEP
javalogging
stefan.m
stefan.m

Reputation: 2012

NullPointerException at java.util.logging.Logger.demandLogger

After upgrading from Java 6 to Java 8, my application throws the following exception:

com.mathworks.toolbox.javabuilder.MWException: Java exception occurred: 
java.lang.NullPointerException
    at java.util.logging.Logger.demandLogger(Logger.java:451)
    at java.util.logging.Logger.getLogger(Logger.java:502)
    at com.mathworks.toolbox.javabuilder.internal.MWMCR.mclFeval(Native Method)
    at com.mathworks.toolbox.javabuilder.internal.MWMCR.access$600(MWMCR.java:23)
    at com.mathworks.toolbox.javabuilder.internal.MWMCR$6.mclFeval(MWMCR.java:833)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:483)
    at com.mathworks.toolbox.javabuilder.internal.MWMCR$5.invoke(MWMCR.java:731)
    at com.sun.proxy.$Proxy2.mclFeval(Unknown Source)
    at com.mathworks.toolbox.javabuilder.internal.MWMCR.invoke(MWMCR.java:406)
    at mDataEngine.mDataEngineMIF.volatility(mDataEngineMIF.java:7212)

This occurs when using the mathworks library, which in turn uses java.util.logging.Logger where the exception is thrown.

Upvotes: 2

Views: 3364

Answers (2)

jmehrens
jmehrens

Reputation: 11045

The Oracle bug JDK-8145302 NullPointerException at java.util.logging.Logger.demandLogger has been replaced with

JDK-8177325 Caller sensitive methods Logger.getLogger, Logger.getAnonymousLogger, will throw NPE if there is no caller on the stack.

The workaround in that bug report is listed as:

Workaround: use an auxiliary class in order to call Logger.getLogger instead of calling Logger::getLogger directly from JNI.

As you can see from your stacktrace:

java.lang.NullPointerException
at java.util.logging.Logger.demandLogger(Logger.java:451)
at java.util.logging.Logger.getLogger(Logger.java:502)
at com.mathworks.toolbox.javabuilder.internal.MWMCR.mclFeval(Native Method) 
...

the com.mathworks.toolbox.javabuilder.internal.MWMCR.mclFeval is a JNI method calling java.util.logging.Logger.getLogger.

Mathworks should update the MWMCR class to include a java helper method to invoke getLogger and that helper method should be called from JNI instead of getLogger directly.

Upvotes: 1

stefan.m
stefan.m

Reputation: 2012

This can be solved by setting the following system property when starting the Java program:

-Dsun.util.logging.disableCallerCheck=true

More detailed information:

The reason for the NullpointerException seems to be explained here: http://www.infoq.com/news/2013/07/Oracle-Removes-getCallerClass

The method getCallerClass is used here in java.util.logging.Logger:

 public static Logger More ...getLogger(String name) {
     return demandLogger(name, null, Reflection.getCallerClass());
 }

This leads to the variable caller to be null in the following code of java.util.logging.Logger:

     if (sm != null && !SystemLoggerHelper.disableCallerCheck) {
         if (caller.getClassLoader() == null) {
             return manager.demandSystemLogger(name, resourceBundleName);
         }
     }
     return manager.demandLogger(name, resourceBundleName, caller);

By setting the systemvariable as explained above, the caller variable will not be used.

Upvotes: 2

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