java - "javac -version"抛出 Unsupported major.minor version 52.0，我的符号链接(symbolic link)不正确吗？

Question

这些在我的 /usr/bin 中:

lrwxr-xr-x   1 root   wheel        73 Aug 21 18:18 javap -> /Library/Java/JavaVirtualMachines/jdk1.7.0_67.jdk/Contents/Home/bin/javap
lrwxr-xr-x   1 root   wheel        73 Aug 21 18:18 javah -> /Library/Java/JavaVirtualMachines/jdk1.7.0_67.jdk/Contents/Home/bin/javah
lrwxr-xr-x   1 root   wheel        82 Aug 21 18:18 javafxpackager -> /Library/Java/JavaVirtualMachines/jdk1.7.0_67.jdk/Contents/Home/bin/javafxpackager
lrwxr-xr-x   1 root   wheel        75 Aug 21 18:18 javadoc -> /Library/Java/JavaVirtualMachines/jdk1.7.0_67.jdk/Contents/Home/bin/javadoc
lrwxr-xr-x   1 root   wheel        73 Aug 21 18:18 javac -> /Library/Java/JavaVirtualMachines/jdk1.7.0_67.jdk/Contents/Home/bin/javac
lrwxr-xr-x   1 root   wheel        72 Aug 21 18:18 java -> /Library/Java/JavaVirtualMachines/jdk1.7.0_67.jdk/Contents/Home/bin/java

它们都指向 JDK v1.7.x。

我正在运行 Max OS X 10.9.4。我愚蠢地试图从 1.8 降级到 1.7，这导致了这些问题。尝试运行 javac -version 会抛出此堆栈跟踪:

zhickman:bin zhickman$ javac -version
Exception in thread "main" java.lang.UnsupportedClassVersionError: com/sun/tools/javac/Main : Unsupported major.minor version 52.0
    at java.lang.ClassLoader.defineClass1(Native Method)
    at java.lang.ClassLoader.defineClass(ClassLoader.java:800)
    at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142)
    at java.net.URLClassLoader.defineClass(URLClassLoader.java:449)
    at java.net.URLClassLoader.access$100(URLClassLoader.java:71)
    at java.net.URLClassLoader$1.run(URLClassLoader.java:361)
    at java.net.URLClassLoader$1.run(URLClassLoader.java:355)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.net.URLClassLoader.findClass(URLClassLoader.java:354)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:425)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:412)
    at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:308)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:358)
    at sun.launcher.LauncherHelper.checkAndLoadMain(LauncherHelper.java:482)

但是，运行 java -version 给我:

zhickman:bin zhickman$ java -version
java version "1.7.0_67"
Java(TM) SE Runtime Environment (build 1.7.0_67-b01)
Java HotSpot(TM) 64-Bit Server VM (build 24.65-b04, mixed mode)

我想我错误地更新了我的符号链接(symbolic link)。我知道“Unsupported major.minor version...”错误很常见，但我只看到涉及尝试运行编译代码的解决方案会导致此问题。

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补充说明:

zhickman:bin zhickman$ $JAVA_HOME
/Library/Java/JavaVirtualMachines/jdk1.7.0_67.jdk/Contents/Home

Answer 1

事实证明我需要删除 /Library/Java/Extensions，其中包含我假设引用了 JRE8 的 tools.jar。