我正在从事Java7开发,我已经将JDK7添加到了Java中,并在项目属性中选择了它。warning: java/lang/Boolean.class(java/lang:Boolean.class): major version 51 is newer than 50, the highest major version supported by this compiler.和/A
我试图安装JDK1.7sudo apt update但是得到下面的错误Building dependency tree Package openjdk-7-jdk is not available, but is referred to by another package.
This may mean