在用idea软件run的时候显示：

  

（objc[23229]: Class JavaLaunchHelper is implemented in both /Library/Java/JavaVirtualMachines/jdk1.7.0_80.jdk/Contents/Home/bin/java (0x10af154c0) and     /Library/Java/JavaVirtualMachines/jdk1.7.0_80.jdk/Contents/Home/jre/lib/libinstrument.dylib (0x10afd04e0). One of the two will be used. Which one is undefined.）

解决办法：

1.点击IntelliJ IDEA最上面菜单的”Help”下的“Edit Custom Properties”，没有这个properties文件的话，IntelliJ IDEA会提示创建;
2.在文件中加上
idea.no.launcher=true
3.重启IntelliJ IDEA

原因分析：

You can find all the details here:

IDEA-170117 “objc: Class JavaLaunchHelper is implemented in both …” warning in Run consoles
It’s the old bug in Java on Mac that got triggered by the Java Agent being used by the IDE when starting the app. This message is harmless and is safe to ignore. Oracle developer’s comment:

The message is benign, there is no negative impact from this problem since both copies of that class are identical (compiled from the exact same source). It is purely a cosmetic issue.

The problem is fixed in Java 9 and in Java 8 update 152.

If it annoys you or affects your apps in any way, the workaround for IntelliJ IDEA is to disable idea_rt launcher agent by adding idea.no.launcher=true into idea.properties (Help | Edit Custom Properties...).

Mac上面Java的一个老Bug了，会在那些使用了Java Agent的IDE上运行应用时触发，但这个Error对程序是无影响的，可以无视