TestIPC occassionally fails with BindException

org.apache.hadoop.ipc.TestIPC.testParallel occassionally fails with

java.net.BindException: Address already in use
at sun.nio.ch.Net.bind(Native Method)
at sun.nio.ch.ServerSocketChannelImpl.bind(ServerSocketChannelImpl.java:119)
at sun.nio.ch.ServerSocketAdaptor.bind(ServerSocketAdaptor.java:59)
at org.apache.hadoop.ipc.Server$Listener.<init>(Server.java:161)
at org.apache.hadoop.ipc.Server.start(Server.java:607)
at org.apache.hadoop.ipc.TestIPC.testParallel(TestIPC.java:174)
at org.apache.hadoop.ipc.TestIPC.testParallel(TestIPC.java:164)

My guess is that port 1234 used by TestIPC.testSerial hasn't been cleaned up by the time TestIPC.testParallel tries to use it. The failure rate of this test seems around 5%.