相关疑难解决方法(0)

我在Mac OS X v10.8(Mountain Lion)上安装了JDK.当我将它升级到Mac OS X v10.9(Mavericks)并在终端中运行时,它显示:java -version

没有Java运行时,请求安装.

然后我在Mac上手动安装了JDK(1.7).似乎安装工作正常.安装完成后,我打开终端并输入java -version.它也显示了同样的错误:

没有Java运行时,请求安装.

我怎么解决这个问题？

可能重复:
不支持的主要.minor版本51.0

我正在尝试构建一个应用程序,但它给出了一些错误.我的JDK版本如下:

java version "1.6.0_30"
Java(TM) SE Runtime Environment (build 1.6.0_30-b12)
Java HotSpot(TM) Client VM (build 20.5-b03, mixed mode, sharing)

这是我的错误日志:

Buildfile: build.xml

compile:
     [echo] Compiling the service....
     [echo]   ...mkdir for classes first....
     [echo]   ...java classes next....
     [echo]   ...mkdir for generated code next....
     [echo]  ...generate stubs/skeletons next....
[wscompile] command line: wscompile -d /home/vivekray/program/MTrans/WEB-INF/classes -features:wsi,documentliteral -gen:server -keep -model /home/vivekray/program/MTrans/WEB-INF/model.gz -verbose -Xprintstacktrace /home/vivekray/program/MTrans/src/config.xml -classpath /home/vivekray/program/MTrans/WEB-INF:/home/vivekray/program/MTrans/WEB-INF/classes:/home/vivekray/program/MTrans/lib/log4j-1.2.16.jar:/home/vivekray/jwsdp-2.0/jwsdp-shared/lib/mail.jar:/home/vivekray/jwsdp-2.0/jwsdp-shared/lib/activation.jar:/home/vivekray/jwsdp-2.0/jaxp/lib/jaxp-api.jar:/home/vivekray/jwsdp-2.0/jaxp/lib/endorsed/dom.jar:/home/vivekray/jwsdp-2.0/jaxp/lib/endorsed/sax.jar:/home/vivekray/jwsdp-2.0/jaxp/lib/endorsed/xalan.jar:/home/vivekray/jwsdp-2.0/jaxp/lib/endorsed/xercesImpl.jar:/home/vivekray/jwsdp-2.0/jaxrpc/lib/jaxrpc-api.jar:/home/vivekray/jwsdp-2.0/jaxrpc/lib/jaxrpc-spi.jar:/home/vivekray/jwsdp-2.0/jaxrpc/lib/jaxrpc-impl.jar:/home/vivekray/jwsdp-2.0/saaj/lib/saaj-api.jar:/home/vivekray/jwsdp-2.0/saaj/lib/saaj-impl.jar:/home/vivekray/jwsdp-2.0/jwsdp-shared/lib/relaxngDatatype.jar:/home/vivekray/jwsdp-2.0/jwsdp-shared/lib/xsdlib.jar:/home/vivekray/jwsdp-2.0/jwsdp-shared/lib/jax-qname.jar:/home/vivekray/jwsdp-2.0/apache-ant/lib/ant.jar:/home/vivekray/jwsdp-2.0/fastinfoset/lib/FastInfoset.jar:/home/vivekray/Softwares/apache-tomcat-7.0.27/lib/servlet-api.jar
[wscompile] [creating model: mtransservice]
[wscompile] [creating service: Mtransservice]

BUILD FAILED
java.lang.UnsupportedClassVersionError: in/cdac/mobile/computing/mtrans/MtransService : Unsupported major.minor version …

我有两个JDK,用于Java 6和7.

我想用两者构建我的项目.最初我们只针对1.6构建.我在项目设置中看到我可以选择1.5,1.6 1.7作为编译器级别.

如何将这些选项添加到IDE中？我从未安装过Java 1.5.假设我想要Java 1.4.如何让它出现在列表中？我在IDE首选项中添加了两个不同的JRE,但这些不是下拉列表中显示的内容.

我在OSX上从JDK 1.7升级到问题 - > 1.8.升级已经完成,但javac仍然返回1.7作为版本.

我从Oracle的主页下载了JDK 8_u5,然后运行安装程序.

我还在安装后采取了以下步骤:

> export JAVA_HOME=`/usr/libexec/java_home -v 1.8`  (Executed in my .bashrc file)

> echo $JAVA_HOME
/Library/Java/JavaVirtualMachines/jdk1.8.0_05.jdk/Contents/Home

> javac -version
javac 1.7.0_21

> $JAVA_HOME/bin/javac -version
javac 1.7.0_21

> $JAVA_HOME/bin/java -version    
java version "1.8.0_05"
Java(TM) SE Runtime Environment (build 1.8.0_05-b13)
Java HotSpot(TM) 64-Bit Server VM (build 25.5-b02, mixed mode)

我已经完成并删除了Java 1.7(和所有其他JDK版本),然后重新运行安装程序:

> ls /Library/Java/JavaVirtualMachines
jdk1.8.0_05.jdk

仍然没有用,javac报告版本为1.7.0_21

> which javac
/usr/bin/javac

> ls -ltra /usr/bin/javac 
[snipped] /usr/bin/javac -> /System/Library/Frameworks/JavaVM.framework/Versions/Current/Commands/javac

在该路径中,Current是一个符号链接A.内容A/Commands …