"org.eclipse.m2e.jdt.JarLifecycleMapping" is not available
that's what i did on STS to resolve this issue:
1) Right-click on your project, select Maven -> Disable Maven Nature.
2) Right-click on your project, select spring tools -> update maven dependencies
3) Right click on your Project and select “Configure -> Convert into Maven Project”
Today i had the same problem and found this page by google.
My solution to resolve the problem right click on the project then click Maven > Update Project... then click OK. That´s all!