This happens when your maven project uses different Compiler Compliance level and Eclipse IDE uses different Compiler Compliance level. In order to fix this we need to change the Compiler Compliance level of Maven project to the level IDE uses.
1) To See Java Compiler Compliance level uses in Eclipse IDE
*) Window -> Preferences -> Compiler -> Compiler Compliance level : 1.8 (or 1.7, 1.6 ,, ect)
2) To Change Java Compiler Compliance level of Maven project
*) Go to "Project" -> "Properties" -> Select "Java Compiler" -> Change the Compiler Compliance level : 1.8 (or 1.7, 1.6 ,, ect)