This compilation unit is not on the build path of a Java project

Question

When I try to use ctrl+space this error is shown:

This compilation unit is not on the build path of a Java project.

I see tha

Answer 1

Add this to .project file

 <?xml version="1.0" encoding="UTF-8"?>
        <projectDescription>
            <name>framework</name>
            <comment></comment>
            <projects>
            </projects>
            <buildSpec>
                <buildCommand>
                    <name>org.eclipse.wst.common.project.facet.core.builder</name>
                    <arguments>
                    </arguments>
                </buildCommand>
                <buildCommand>
                    <name>org.eclipse.jdt.core.javabuilder</name>
                    <arguments>
                    </arguments>
                </buildCommand>
                <buildCommand>
                    <name>org.eclipse.m2e.core.maven2Builder</name>
                    <arguments>
                    </arguments>
                </buildCommand>
                <buildCommand>
                    <name>org.eclipse.wst.validation.validationbuilder</name>
                    <arguments>
                    </arguments>
                </buildCommand>
            </buildSpec>
            <natures>
                <nature>org.eclipse.jem.workbench.JavaEMFNature</nature>
                <nature>org.eclipse.wst.common.modulecore.ModuleCoreNature</nature>
                <nature>org.eclipse.jdt.core.javanature</nature>
                <nature>org.eclipse.m2e.core.maven2Nature</nature>
                <nature>org.eclipse.wst.common.project.facet.core.nature</nature>
            </natures>
        </projectDescription>

Answer 2

For those who still have problems after attempting the suggestions above: I solved the issue by updating the maven project.