When trying to start hadoop, this error message is quite common : Exception in thread "main" java.lang.NoClassDefFoundError: start-all/sh Caused by: java.lang.ClassNotFoundException: start-all.sh at java.net.URLClassLoader$1.run(URLClassLoader.java:202) at java.security.AccessController.doPrivileged(Native Method) at … [Read more...] about Exception in thread “main” java.lang.NoClassDefFoundError: start-all/sh Error