Stash crashes due to java.lang.OutOfMemoryError PermGen Space Error

Symptoms

Stash crashes. The following appears in the atlassian-stash.log:

java.lang.OutOfMemoryError: PermGen space

Cause

What does it generally mean?

The error message java.lang.OutOfMemoryError: PermGen space this means Java's fixed block for loading class files has been exceeded. Permanent Generation Memory, unlike Java heap space, is the memory allocation for the classes themselves as opposed to the objects created. The addition of more plugins contributes to more consumption of PermGen space and is usually the cause of this error. The error occurs when enough classes are invoked.

Why does it fail if I copy a setenv.sh from a previous version into the binaries shipped with Stash 3.8+?

A little more context on the change that likely triggered this issue if the setenv.sh file was copied from an older version into <Stash 3.8 installation directory>/bin is that, as of Stash 3.8 we removed the permgen.sh script that checked if PermGen is supported (the suppport to PermGen been removed in Java 8).

The differences in the setenv.sh can be seen below:

 JAVA_OPTS="-Xms${JVM_MINIMUM_MEMORY} -Xmx${JVM_MAXIMUM_MEMORY} ${JMX_OPTS} ${JAVA_OPTS} ${JVM_REQUIRED_ARGS} ${JVM_SUPPORT_RECOMMENDED_ARGS} ${STASH_HOME_MINUSD}"

# PermGen size needs to be increased if encountering OutOfMemoryError: PermGen problems. Specifying PermGen size is
# not valid on IBM JDKs
STASH_MAX_PERM_SIZE=256m
if [ -f "${PRGDIR}/permgen.sh" ]; then
    echo "Detecting JVM PermGen support..."
    . "${PRGDIR}/permgen.sh"
    if [ $JAVA_PERMGEN_SUPPORTED = "true" ]; then
        echo "PermGen switch is supported. Setting to ${STASH_MAX_PERM_SIZE}\n"
        JAVA_OPTS="-XX:MaxPermSize=${STASH_MAX_PERM_SIZE} ${JAVA_OPTS}"
    else
        echo "PermGen switch is NOT supported and will NOT be set automatically.\n"
    fi
fi

JAVA_OPTS="-Xms${JVM_MINIMUM_MEMORY} -Xmx${JVM_MAXIMUM_MEMORY} ${JAVA_OPTS} ${JVM_REQUIRED_ARGS} ${JVM_SUPPORT_RECOMMENDED_ARGS} ${STASH_HOME_MINUSD}"

# PermGen size needs to be increased if encountering OutOfMemoryError: PermGen problems.
MAX_PERM_SIZE=256m
JAVA_OPTS="-XX:MaxPermSize=${MAX_PERM_SIZE} ${JAVA_OPTS}"

export JAVA_OPTS

From the scripts above, if setenv.sh was copied over from Stash 3.7- to an environment running on Java 7, the test to check if using PermGen is allowed always returns false since permgen.sh is no longer shipped with Stash 3.8+ and the PermGen size gets set to the default in Java 7, which is too small for Stash and causes the Out of Memory Error.

Resolution