不支持的major.minor版本52.0使用ant

Question

我正在尝试编译ics-openconnect android应用程序(https://github.com/cernekee/ics-openconnect).

我跟着'ReadMe'.但是,当我尝试调试时,它会发生错误.

错误:

-dex:
  [dex] input: /home/yj/ics-openconnect/bin/classes
  [dex] input: /home/yj/ics-openconnect/libs/openconnect-wrapper.jar
  [dex] input: /home/yj/ics-openconnect/libs/acra-4.5.0.jar
  [dex] input: /home/yj/ics-openconnect/libs/stoken-wrapper.jar
  [dex] Pre-Dexing /home/yj/ics-openconnect/libs/openconnect-wrapper.jar -> openconnect-wrapper-58de756051305e9ad3753d649df24013.jar
   [dx] Exception in thread "main" java.lang.UnsupportedClassVersionError: com/android/dx/command/Main : Unsupported major.minor version 52.0
   [dx]     at java.lang.ClassLoader.defineClass1(Native Method)
   [dx]     at java.lang.ClassLoader.defineClassCond(ClassLoader.java:631)
   [dx]     at java.lang.ClassLoader.defineClass(ClassLoader.java:615)
   [dx]     at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:141)
   [dx]     at java.net.URLClassLoader.defineClass(URLClassLoader.java:283)
   [dx]     at java.net.URLClassLoader.access$000(URLClassLoader.java:58)
   [dx]     at java.net.URLClassLoader$1.run(URLClassLoader.java:197)
   [dx]     at java.security.AccessController.doPrivileged(Native Method)
   [dx]     at java.net.URLClassLoader.findClass(URLClassLoader.java:190)
   [dx]     at java.lang.ClassLoader.loadClass(ClassLoader.java:306)
   [dx]     at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:301)
   [dx]     at java.lang.ClassLoader.loadClass(ClassLoader.java:247)
   [dx] Could not find the main class: com.android.dx.command.Main. Program will exit.

BUILD FAILED

而且,我的java:

$java -version
java version "1.6.0_45"
Java(TM) SE Runtime Environment (build 1.6.0_45-b06)
Java HotSpot(TM) 64-Bit Server VM (build 20.45-b01, mixed mode)

javac的:

$javac -version
javac 1.6.0_45

我知道版本52.0意味着'jdk 1.8',但我只安装了jdk 1.6

我该怎么解决？

Answer 1

你的问题实际上包含答案.每个类都有版本字段,其中包含两个单词:Major和Minor版本号.该版本遵循java签名"CAFEBABE".对于要加载的类,签名必须正确,主要版本应小于或等于活动JRE(Java运行时环境)支持的版本.换句话说,如果要加载主要版本字设置为52的类,则应使用Java 8运行时.否则,您将获得输出中显示的异常.所以只有两个选项:1:安装Java 8运行时.或者2:仅使用使用Java 6 SDK构建的软件包.