RFR: 8364227: MBeanServer registerMBean throws NPE

[Kevin Walls]

A long-standing omission where MBeanServer.registerMBean documents exception behaviour, but we actually throw an NPE.  We should recognise a null object and return the wrapped exception we document.

This wrapping behaviour is common elsewhere in this area, e.g. unregisterMBean which checks for a null name and throws RuntimeOperationsException.

Docs:
https://docs.oracle.com/en/java/javase/24/docs/api/java.management/javax/management/MBeanServer.html#registerMBean(java.lang.Object,javax.management.ObjectName)

Throws:
RuntimeOperationsException - Wraps a java.lang.IllegalArgumentException: The object passed in parameter is null or no object name is specified.


Current behaviour:


$ java MBS_NPE.java
Exception in thread "main" java.lang.NullPointerException: Cannot invoke "Object.getClass()" because "object" is null
        at java.management/com.sun.jmx.interceptor.DefaultMBeanServerInterceptor.registerMBean(DefaultMBeanServerInterceptor.java:296)
        at java.management/com.sun.jmx.mbeanserver.JmxMBeanServer.registerMBean(JmxMBeanServer.java:511)
        at MBS_NPE.main(MBS_NPE.java:11)


Should be changed to:


$ java MBS_NPE.java
javax.management.RuntimeOperationsException: Exception occurred trying to register the MBean
        at java.management/com.sun.jmx.interceptor.DefaultMBeanServerInterceptor.registerMBean(DefaultMBeanServerInterceptor.java:297)
        at java.management/com.sun.jmx.mbeanserver.JmxMBeanServer.registerMBean(JmxMBeanServer.java:511)
        at MBS_NPE.main(MBS_NPE.java:11)
        at java.base/jdk.internal.reflect.DirectMethodHandleAccessor.invoke(DirectMethodHandleAccessor.java:104)
        at java.base/java.lang.reflect.Method.invoke(Method.java:565)
        at jdk.compiler/com.sun.tools.javac.launcher.SourceLauncher.execute(SourceLauncher.java:258)
        at jdk.compiler/com.sun.tools.javac.launcher.SourceLauncher.run(SourceLauncher.java:138)
        at jdk.compiler/com.sun.tools.javac.launcher.SourceLauncher.main(SourceLauncher.java:76)
Caused by: java.lang.IllegalArgumentException: Object cannot be null
        at java.management/com.sun.jmx.interceptor.DefaultMBeanServerInterceptor.registerMBean(DefaultMBeanServerInterceptor.java:295)
        ... 7 more

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Commit messages:
 - 8364227: MBeanServer registerMBean throws NPE

Changes: https://git.openjdk.org/jdk/pull/26548/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=26548&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8364227
  Stats: 8 lines in 1 file changed: 5 ins; 0 del; 3 mod
  Patch: https://git.openjdk.org/jdk/pull/26548.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/26548/head:pull/26548

PR: https://git.openjdk.org/jdk/pull/26548