java.lang.OutOfMemoryError: PermGen when using groovy scripts

Issue

• We exhaust our PermGen space and see thousands of Script# classes loaded by groovy.lang.GroovyClassLoader$InnerLoaders. The heap dump shows them retained in GroovyClassLoader's classCache:

Class Name                                                                                                          | Ref. Objects | Shallow Heap | Ref. Shallow Heap | Retained Heap 
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gs groovy.lang.GroovyShell @ 0x707b3bbe0                                              |       30,682 |            56 |         6,381,856 |            88 
 '- loader groovy.lang.GroovyClassLoader @ 0x707b3bf20                    |       30,682 |          192 |         6,381,856 |     1,999,032 
    '- classCache java.util.HashMap @ 0x707b3c388                                  |       30,682 |            72 |         6,381,856 |     1,997,120 
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