java.lang.UnsupportedClassVersionError major.minor version 49.0
java.lang.UnsupportedClassVersionError: com/sun/tools/javac/Main (Unsupported major.minor version 49.0) Solution:- If you are using 1.5 version of java so please update 1.6 version of java For Eclipse 3.1 setting. Right click on your project --> Popup window will be opend --> select java build path in left side navigation bar --> Click JRE System LIbrary --> edit button --> Choose Alternate JRE: and click on Installed JREs... button. --> new Popup will be opened --> Click JRE home directory: browse... button --> and select java 1.6.0 directory. --> Write JRE name --> Click Ok button. --> Select your new jre and click ok button. --> then Select Alternate JRE from drop down list. --> Click on Finish.