Environment: jdk1.7
javax.servlet-api-3.0.1.jar is needed for this test.
Reproduce steps:
javac Test1.java -cp javax.servlet-api-3.0.1.jarbuild Test1.java with javax.servlet-api-3.0.1.jarjavac Test2.java -cp javax.servlet-api-3.0.1.jarbuild Test2.java with javax.servlet-api-3.0.1.jarjavac Test3.javabuild Test3.javaBut when this command
java Test3run, Exception is thrown. The result at the end of this post.
Test1.hello()运行正常，而Test2.hello()运行失败
Test1.java
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.io.OutputStream;
public class Test1 {
public void getRequest(HttpServletResponse resp) throws IOException {
OutputStream os = resp.getOutputStream();
resp.getOutputStream().close();
}
public void hello(String world) {
System.out.println("hello " + world);
}
}
Test2.java
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.io.OutputStream;
public class Test2 {
public void getRequest(HttpServletResponse resp) throws IOException {
OutputStream os = resp.getOutputStream();
try {
resp.getOutputStream().close();
} catch (Exception e) {
}
}
public void hello(String world) {
System.out.println("hello " + world);
}
}
Test3.java
public class Test3 {
public static void main(String[] args) {
new Test1().hello("world1");
new Test2().hello("world2");
}
}
output of the final step. Test2.hello("world2") throw an exception:
hello world1
Exception in thread "main" java.lang.NoClassDefFoundError: javax/servlet/ServletOutputStream
at cn.test.abc1.Test3.main(Test3.java:9)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:497)
at com.intellij.rt.execution.application.AppMain.main(AppMain.java:144)
Caused by: java.lang.ClassNotFoundException: javax.servlet.ServletOutputStream
at java.net.URLClassLoader.findClass(URLClassLoader.java:381)
at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:331)
at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
... 6 more
I am very confused with the Exception. Because I didn't use any code in the Class ServletOutputStream. And the difference of the Test1 and Test2 is only a try blocked.