NPE founded in integration test.

[刘正阳 | bytejava.cn]

testJdkProxy(com.github.liuzhengyang.simplerpc.core.ClientBuilderTest)  Time elapsed: 10.111 sec  <<< ERROR!
java.lang.NullPointerException
	at com.github.liuzhengyang.simplerpc.core.proxy.CglibClientProxy$ProxyInteceptor.intercept(CglibClientProxy.java:53)
	at com.github.liuzhengyang.simplerpc.core.IHello$$EnhancerByCGLIB$$719f2977.say(<generated>)
	at com.github.liuzhengyang.simplerpc.core.ClientBuilderTest.proxyTest(ClientBuilderTest.java:57)
	at com.github.liuzhengyang.simplerpc.core.ClientBuilderTest.testJdkProxy(ClientBuilderTest.java:45)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:606)
	at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50)
	at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
	at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47)
	at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
	at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325)
	at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:78)
	at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:57)
	at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
	at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)

https://travis-ci.org/liuzhengyang/simple-rpc/jobs/206051347