如何使用旧版本的java 1.6运行.jar 1.7程序？

Question

我有一个在1.7版本java中运行良好的code.jar，但是当使用另一台带有1.6版本的linux的计算机时，它给我一个错误，我怎么能在1.6版本中运行它？

Answer 1

Use the cross-compilation options when invoking javac .

If only the -target option is specified as recommended in most other replies, the 1.7 SDK will issue a warning about -bootclasspath . That option requires an rt.jar of the target JRE version (note not JDK). It allows the compiler to check that the classes, methods and attributes of the code that reference core Java SE are actually present in the rt.jar . This is very important to ensure compatibility.

Answer 2

如果代码未使用较旧的Java兼容性标志进行编译，则无法在1.6上运行它。

Answer 3

Build the project using Java 6 in eclipse, you will need to download Java 1.6 JRE, then have eclipse point to 1.6 JRE, see: http://www.cleartoolkit.com/dokuwiki/doku.php?id=clearwiki:20.cleardatabuilder:01.setup:01.prerequisites

Now right click on your project -> Properties, click Java Compiler, uncheck "enable project specific settings", click "Configure Workspace Settings" , and select 1.6 as your compiler compliance level.

Do "the thing" to export your project again, the new jar should work.

Hope this helps.

Answer 4

I don't think you can run higher version class with lower version.

Another approach may be while compiling set target version as 1.6.

Example:

javac yourFile.java -target 1.6

Answer 5

I have found a solution within Eclipse!

If you go to your project and right click to access the properties, there is a tab called Java Compiler. If you enable project specific properties and unclick the check box under JDK compliance, you can change the source compatibility and .class files compatibility to be 1.6.

This should fix your problem and the generated .jar file should work on both devices. I tested this by moving a file from 1.8 to 1.7 and testing on my Raspberry Pi that has OpenJDK 1.7 which worked great. I hope this helps.