liunx系统里面从数据库查询大量数据时报如下错，求解

Exception in thread "com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread-#2" java.lang.OutOfMemoryError: Java heap space
        at oracle.jdbc.driver.OracleStatement.prepareAccessors(OracleStatement.java:879)
15:00:13,467 WARN  [ThreadPoolAsynchronousRunner] com.mchange.v2.async.ThreadPoolAsynchronousRunner$DeadlockDetector@7720ff6f -- APPARENT DEADLOCK!!! Creating emergency threads for unassigned pending tasks!
        at oracle.jdbc.driver.OracleStatement.executeMaybeDescribe(OracleStatement.java:1057)
        at oracle.jdbc.driver.T4CPreparedStatement.executeMaybeDescribe(T4CPreparedStatement.java:854)
        at oracle.jdbc.driver.OracleStatement.doExecuteWithTimeout(OracleStatement.java:1154)
        at oracle.jdbc.driver.OraclePreparedStatement.executeInternal(OraclePreparedStatement.java:3370)
        at oracle.jdbc.driver.OraclePreparedStatement.executeQuery(OraclePreparedStatement.java:3415)
        at oracle.jdbc.OracleDatabaseMetaData.getTables(OracleDatabaseMetaData.java:2472)
        at com.mchange.v2.c3p0.impl.DefaultConnectionTester.activeCheckConnectionNoQuery(DefaultConnectionTester.java:185)
        at com.mchange.v2.c3p0.impl.DefaultConnectionTester.activeCheckConnection(DefaultConnectionTester.java:62)
        at com.mchange.v2.c3p0.AbstractConnectionTester.activeCheckConnection(AbstractConnectionTester.java:67)
        at com.mchange.v2.c3p0.impl.C3P0PooledConnectionPool$1PooledConnectionResourcePoolManager.testPooledConnection(C3P0PooledConnectionPool.java:368)
        at com.mchange.v2.c3p0.impl.C3P0PooledConnectionPool$1PooledConnectionResourcePoolManager.refurbishIdleResource(C3P0PooledConnectionPool.java:310)
        at com.mchange.v2.resourcepool.BasicResourcePool$AsyncTestIdleResourceTask.run(BasicResourcePool.java:1999)
        at com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread.run(ThreadPoolAsynchronousRunner.java:547)
15:01:57,923 WARN  [ThreadPoolAsynchronousRunner] com.mchange.v2.async.ThreadPoolAsynchronousRunner$DeadlockDetector@7720ff6f -- APPARENT DEADLOCK!!! Complete Status: 
        Managed Threads: 4
        Active Threads: 3
        Active Tasks: 
                com.mchange.v2.resourcepool.BasicResourcePool$AsyncTestIdleResourceTask@19ece3b5 (com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread-#1)
                com.mchange.v2.resourcepool.BasicResourcePool$AsyncTestIdleResourceTask@f598d5f (com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread-#3)
                com.mchange.v2.resourcepool.BasicResourcePool$AsyncTestIdleResourceTask@40505fd8 (com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread-#0)
        Pending Tasks: 
                com.mchange.v2.resourcepool.BasicResourcePool$AsyncTestIdleResourceTask@5cc47ee4
                com.mchange.v2.resourcepool.BasicResourcePool$1DestroyResourceTask@6866da50
                com.mchange.v2.resourcepool.BasicResourcePool$1DestroyResourceTask@3886efbc
                com.mchange.v2.resourcepool.BasicResourcePool$1DestroyResourceTask@22e53ca2
                com.mchange.v2.resourcepool.BasicResourcePool$1DestroyResourceTask@77efc193
                com.mchange.v2.resourcepool.BasicResourcePool$1DestroyResourceTask@1d8dd769
                com.mchange.v2.resourcepool.BasicResourcePool$AcquireTask@4b393da7
                com.mchange.v2.resourcepool.BasicResourcePool$AcquireTask@1afec586
                com.mchange.v2.resourcepool.BasicResourcePool$AcquireTask@4c59ee42
                com.mchange.v2.resourcepool.BasicResourcePool$AcquireTask@24295637
                com.mchange.v2.resourcepool.BasicResourcePool$AcquireTask@15db476d
Pool thread stack traces:
        Thread[com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread-#1,5,main]
                com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread.run(ThreadPoolAsynchronousRunner.java:562)
        Thread[com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread-#3,5,main]
                com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread.run(ThreadPoolAsynchronousRunner.java:562)
        Thread[com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread-#2,5,]
        Thread[com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread-#0,5,main]
                com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread.run(ThreadPoolAsynchronousRunner.java:562)linuxoracle数据库