1：echo $JAVA_HOME
使用$JAVA_HOME的话能定位JDK的安装路径的前提是配置了环境变量$JAVA_HOME，否则如下所示，根本定位不到JDK的安装路径
[root@localhost ~]# java -version
java version "1.7.0_65"
OpenJDK Runtime Environment (rhel-2.5.1.2.el6_5-x86_64 u65-b17)
OpenJDK 64-Bit Server VM (build 24.65-b04, mixed mode)
[root@localhost ~]# echo $JAVA_HOME
2：which java
首先要申明一下which java是定位不到安装路径的。which java定位到的是java程序的执行路径。那么怎么定位到java的安装路径呢？下面我们来看看例子吧,如下所示：
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[root@localhost ~]# java -versionjava version "1.7.0_51"OpenJDK Runtime Environment (rhel-2.4.5.5.el7-x86_64 u51-b31)OpenJDK 64-Bit Server VM (build 24.51-b03, mixed mode)[root@localhost ~]# which java/usr/bin/java[root@localhost ~]# ls -lrt /usr/bin/javalrwxrwxrwx. 1 root root 22 9月 6 22:51 /usr/bin/java -> /etc/alternatives/java[root@localhost ~]# ls -lrt /etc/alternatives/javalrwxrwxrwx. 1 root root 72 9月 6 22:51 /etc/alternatives/java -> /usr/lib/jvm/java-1.7.0-openjdk-1.7.0.51-2.4.5.5.el7.x86_64/jre/bin/java |
原文：https://www.cnblogs.com/luminccs-5308/p/10043338.html