{"id":60,"date":"2009-10-12T21:18:51","date_gmt":"2009-10-13T04:18:51","guid":{"rendered":"http:\/\/shivdev.com\/blog\/2009\/10\/12\/exception-in-thread-main-javalangnoclassdeffounderror\/"},"modified":"2009-10-12T21:24:25","modified_gmt":"2009-10-13T04:24:25","slug":"exception-in-thread-main-javalangnoclassdeffounderror","status":"publish","type":"post","link":"http:\/\/shivdev.com\/blog\/2009\/10\/12\/exception-in-thread-main-javalangnoclassdeffounderror\/","title":{"rendered":"Exception in thread main java.lang.NoClassDefFoundError"},"content":{"rendered":"<p>After getting used to the spoon-feeding IDE&#8217;s, writing some one-off classes might lead to this Exception.<\/p>\n<blockquote><p> Exception in thread &#8220;main&#8221; java.lang.NoClassDefFoundError: HelloWorld<br \/>\nCaused by: java.lang.ClassNotFoundException: HelloWorld<br \/>\nat java.net.URLClassLoader$1.run(URLClassLoader.java:200)<br \/>\nat java.security.AccessController.doPrivileged(Native Method)<br \/>\nat java.net.URLClassLoader.findClass(URLClassLoader.java:188)<br \/>\nat java.lang.ClassLoader.loadClass(ClassLoader.java:307)<br \/>\nat sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:301)<br \/>\nat java.lang.ClassLoader.loadClass(ClassLoader.java:252)<br \/>\nat java.lang.ClassLoader.loadClassInternal(ClassLoader.java:320)<br \/>\nCould not find the main class: HelloWorld.  Program will exit.<\/p><\/blockquote>\n<p>Very common problem. Your classpath needs a <strong>.:<\/strong> followed by the classpath, to include the class(es) in your current directory.<\/p>\n<blockquote><p> java -cp <strong>.:<\/strong>.\/lib\/mysql.jar HelloWorld<\/p><\/blockquote>\n","protected":false},"excerpt":{"rendered":"<p>After getting used to the spoon-feeding IDE&#8217;s, writing some one-off classes might lead to this Exception. Exception in thread &#8220;main&#8221; java.lang.NoClassDefFoundError: HelloWorld Caused by: java.lang.ClassNotFoundException: HelloWorld at java.net.URLClassLoader$1.run(URLClassLoader.java:200) at java.security.AccessController.doPrivileged(Native Method) at java.net.URLClassLoader.findClass(URLClassLoader.java:188) at java.lang.ClassLoader.loadClass(ClassLoader.java:307) at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:301) at java.lang.ClassLoader.loadClass(ClassLoader.java:252) at java.lang.ClassLoader.loadClassInternal(ClassLoader.java:320) Could not find the main class: HelloWorld. Program will exit. Very common problem. Your [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[11],"tags":[],"_links":{"self":[{"href":"http:\/\/shivdev.com\/blog\/wp-json\/wp\/v2\/posts\/60"}],"collection":[{"href":"http:\/\/shivdev.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/shivdev.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/shivdev.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/shivdev.com\/blog\/wp-json\/wp\/v2\/comments?post=60"}],"version-history":[{"count":0,"href":"http:\/\/shivdev.com\/blog\/wp-json\/wp\/v2\/posts\/60\/revisions"}],"wp:attachment":[{"href":"http:\/\/shivdev.com\/blog\/wp-json\/wp\/v2\/media?parent=60"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/shivdev.com\/blog\/wp-json\/wp\/v2\/categories?post=60"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/shivdev.com\/blog\/wp-json\/wp\/v2\/tags?post=60"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}