Could not find the main class: org.elasticsearch.bootstrap.Elasticsearch. Program will exit.

Exception in thread "main" java.lang.UnsupportedClassVersionError: org/elasticsearch/bootstrap/Elasticsearch : Unsupported major.minor version 51.0

        at java.lang.ClassLoader.defineClass1(Native Method)

        at java.lang.ClassLoader.defineClass(ClassLoader.java:634)

        at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142)

        at java.net.URLClassLoader.defineClass(URLClassLoader.java:277)

        at java.net.URLClassLoader.access$000(URLClassLoader.java:73)

        at java.net.URLClassLoader$1.run(URLClassLoader.java:212)

        at java.security.AccessController.doPrivileged(Native Method)

        at java.net.URLClassLoader.findClass(URLClassLoader.java:205)

        at java.lang.ClassLoader.loadClass(ClassLoader.java:321)

        at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:294)

        at java.lang.ClassLoader.loadClass(ClassLoader.java:266)

Could not find the main class: org.elasticsearch.bootstrap.Elasticsearch. Program will exit.

原因是，elasticsearch需要jdk为1.7，但系统中java版本为1.6。

转自：http://blog.csdn.net/sdlyjzh/article/details/43966031