thread waits in log4j

We are receiving thread locks (PFB the thread dump).Can you give us suggestion why we receive it. Note that we use Java 1.5, weblogic 9.1 , log4j version 1.2.8

[ACTIVE] ExecuteThread: '4' for queue: 'weblogic.kernel.Default (self-tuning)'" daemon prio=2 tid=0x01d332b0 nid=0x23 waiting for monitor entry [0x5fffd000..0x5ffffb10] at org.apache.log4j.Category.callAppenders(Category.java:185) - waiting to lock <0x7c669620> (a org.apache.log4j.spi.RootCategory) at org.apache.log4j.Category.forcedLog(Category.java:372) at org.apache.log4j.Category.log(Category.java:864) at org.apache.commons.logging.impl.Log4JLogger.debug(Log4JLogger.java:110) at org.hibernate.loader.Loader.doQuery(Loader.java:687) at org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:224) at org.hibernate.loader.Loader.doList(Loader.java:2150) at org.hibernate.loader.Loader.listIgnoreQueryCache(Loader.java:2029) at org.hibernate.loader.Loader.list(Loader.java:2024) at org.hibernate.loader.hql.QueryLoader.list(QueryLoader.java:369) at org.hibernate.hql.ast.QueryTranslatorImpl.list(QueryTranslatorImpl.java:300) at org.hibernate.engine.query.HQLQueryPlan.performList(HQLQueryPlan.java:146) at org.hibernate.impl.SessionImpl.list(SessionImpl.java:1093) at org.hibernate.impl.QueryImpl开发者_如何转开发.list(QueryImpl.java:79) at com.lks.myapp.data.dao.SourceCheckImpl.getSources(SourceCheckImpl.java:87)

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Switch to logback for high performance logging. Log4j is having performance issues. We have done the same in one of our products