GC problem when having Spring jars in a higher ClassLoader without using clearClassLoader [SPR-7227]

[spring-projects-issues]

Thomas Risberg opened SPR-7227 and commented

GC problem when re-deploying bundles in dm Server 2.0.1. Looks like the GenericTypeAwarePropertyDescriptor is holding a reference to the class.

Class Name | Shallow Heap | Retained Heap

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class com.test.Bean1 @ 0x2c34fb70 | 0 | 0
'- beanClass org.springframework.beans.GenericTypeAwarePropertyDescriptor @ 0x26c94110 | 96 | 152
'- value java.util.HashMap$Entry @ 0x26c92970 | 24 | 176
'- [3] java.util.HashMap$Entry[16] @ 0x26c91740 | 80 | 376
'- table java.util.HashMap @ 0x26c868d8 | 40 | 416
'- propertyDescriptorCache org.springframework.beans.CachedIntrospectionResults @ 0x26c74858 | 16 | 4,136
'- value java.util.WeakHashMap$Entry @ 0x26c5e7e0 | 40 | 4,176
'- [2] java.util.WeakHashMap$Entry[16] @ 0x26230850 | 80 | 98,408
'- table java.util.WeakHashMap @ 0x2622bb40 | 48 | 98,488
'- m java.util.Collections$SynchronizedMap @ 0x262275d8 | 32 | 98,520
'- classCache class org.springframework.beans.CachedIntrospectionResults @ 0x2bc554c8| 16 | 98,704
'- [157] java.lang.Object[320] @ 0x26229208 | 1,296 | 101,208

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Affects: 3.0.2

Issue Links:

• [Performance] CachedIntrospectionResults has wrong approach to caching. [SPR-4876] #9552 [Performance] CachedIntrospectionResults has wrong approach to caching.

[spring-projects-issues]

Glyn Normington commented

Please note that dm Server 2.0.x and Virgo users can upgrade the version of Spring used by applications. To do this, replace all the Spring framework bundles and the file org.springframework.spring-library-3.0.0.RELEASE.libd in repository/ext with a version of these files fixing this issue (target = 3.0.3) and clean start the server. Note that it is essential to replace those files in repository/ext and not mix Spring versions otherwise resolution failure will occur.

[spring-projects-issues]

Juergen Hoeller commented

I've revised CachedIntrospectionResults to only cache GenericTypeAwarePropertyDescriptors if fully safe. So if the Spring jars live in a higher ClassLoader and nobody called acceptClassLoader, we're only caching the basic JDK PropertyDescriptors, rebuilding our GenericTypeAwarePropertyDescriptor decorators on the fly as needed. This should be a good compromise between those different scenarios - reasonably efficient and with no potential for leaking.

Juergen