@Override
    protected void setClassCacheEntry(final Class cls) {
        this.classSoftCache.put(cls.getName(), cls);
    }
A {@code GroovyClassLoader} extension that uses a {@link ManagedConcurrentValueMap} configured with soft references.
In this way, the classloader will "forget" scripts allowing them to be garbage collected and thus prevent memory
issues in JVM metaspace.

@author Stephen Mallette (http://stephen.genoprime.com)
gremlin-groovy/src/main/java/org/apache/tinkerpop/gremlin/groovy/jsr223/GremlinGroovyClassLoader.java