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 ------------- 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
