Have a look at the Eclipse error log. I recently saw following error there:
Error logged from Ant UI:
java.net.SocketTimeoutException: Accept timed out at java.net.DualStackPlainSocketImpl.waitForNewConnection(Native Method) at java.net.DualStackPlainSocketImpl.socketAccept(DualStackPlainSocketImpl.java:135) at java.net.AbstractPlainSocketImpl.accept(AbstractPlainSocketImpl.java:404) at java.net.PlainSocketImpl.accept(PlainSocketImpl.java:199) at java.net.ServerSocket.implAccept(ServerSocket.java:545) at java.net.ServerSocket.accept(ServerSocket.java:513) at org.eclipse.ant.internal.launching.launchConfigurations.RemoteAntBuildListener$ServerConnection.run(RemoteAntBuildListener.java:89)
A Windows reboot solved the problem.
我是重启了eclipse就好了