add chinese for pages.cn/linux/add-apt-respository.md

pages.cn/common/java.md

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+# java
+
+> Java Application Launcher.
+
+- Execute a java .class file that contains a main method by using just the class name:
+
+`java {{classname}}`
+
+- Execute a .jar program:
+
+`java -jar {{filename.jar}}`
+
+- Display JDK, JRE and HotSpot versions:
+
+`java -version`