Eclipse Debugging cannot enter breakpoints

Eclipse setting a breakpoint on a line or popping an error while debugging "Unable to install breakpoint due to missing lines number attributes,modify compiler options to ge Nerate line number Attributes "

This error finds a summary of the solution:
1, when using ant compile, do not open the debug switch, write Javac task to confirm debug=true, otherwise can not debug. the settings for the Eclipse compiler don ' t affect the ant build and even if you launch the ant build from within ECL Ipse. Ant controls it ' s own compiler settings.you can tell ant-Generate debugging info like this ' Javac ... debug= "true" .../& gt; (my problem is for this reason);
2, the compiler setup problem, Window->preferences->java->compiler in the compiler start page, Classfile generation area confirmed that has checked all line Number attributes to generated class files. If it is already checked, please apply it again from the new. or set from the project level, the project Properties->java compiler also on the start page, making sure that you have checked

Second, if the above two points are not a problem, then you compile the project (build), it is best to build project all, because this problem sometimes you add a new project in the Workpence.

Eclipse Debugging cannot enter breakpoints