JpaClassUtils.isOfType performance improvement [DATAJPA-941]

[spring-projects-issues]

Milan Mimica opened DATAJPA-941 and commented

Current implementation of boolean org.springframework.data.jpa.provider.JpaClassUtils.isOfType(Object source, String typeName, ClassLoader classLoader) is slow because it's written around exception handling. Making an instance of an exception in java is quite expensive, especially before JVM optimisations kick in.
Example of a stack trace:

java.lang.Throwable.fillInStackTrace(Native Method)
java.lang.Throwable.fillInStackTrace(Throwable.java:783)
java.lang.Throwable.<init>(Throwable.java:265)
java.lang.Exception.<init>(Exception.java:66)
java.lang.RuntimeException.<init>(RuntimeException.java:62)
java.lang.ClassCastException.<init>(ClassCastException.java:58)
java.lang.Class.cast(Class.java:3369)
org.springframework.data.jpa.provider.JpaClassUtils.isOfType(JpaClassUtils.java:60)
org.springframework.data.jpa.provider.JpaClassUtils.isEntityManagerOfType(JpaClassUtils.java:46)
org.springframework.data.jpa.provider.PersistenceProvider.fromEntityManager(PersistenceProvider.java:294)
org.springframework.data.jpa.repository.query.PartTreeJpaQuery$QueryPreparer.createCreator(PartTreeJpaQuery.java:190)
...

The fix to simply replace it with boolean java.lang.Class.isInstance(Object obj)

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Referenced from: pull request #177

Backported to: 1.10.3 (Hopper SR3), 1.9.5 (Gosling SR5)