Open Liberty

Segmentation Fault in Debug Mode

Segmentation Fault: An event resulting in exit code 139. It occurs when a process receives a SIGSEGV signal, which is generated when the operating system detects that the process is trying to access memory that either does not exist or that it lacks permission to access.

Start Open Liberty in Debug Mode

-Dwas.debug.mode=true (1)
-Dsun.reflect.noInflation=true (2)
-agentlib:jdwp=transport=dt_socket,server=y,suspend=n,address=7777 (3)

java

1	Specific to WebSphere-based servers, including Open Liberty. Enables the internal debugging mode, which modifies how the JVM and Open Liberty handle debugging-related optimizations.
2	`sun.reflect.noInflation=true` enables immediate inflation on all method invocations. In general, inflated Java bytecode accessors are faster than native JNI accessors, at the cost of additional native and Java memory usage.
3	Enables Java Debug Wire Protocol (JDWP) for remote debugging

Forgetting to set sun.reflect.noInflation JVM property in Debug Mode can cause Segmentation Fault, for example, during the invocation of ⚪ Session#flush() in Hibernate. You might forget to set this JVM property when starting Open Liberty with ws-server.jar. However, if you use the server script, it is automatically included.

The sun.reflect.noInflation=true JVM property was added to server script as a fix for Issue #1091 - Fix for Hot code replace in JAX-RS applications