The Maven engineering POM defines the JDK version

Today, I took the previous project into eclipse and found the error, some classes are not supported in 1.6, you need to set the JDK version to 1.7, I make changes directly through the prompts in Eclipse, and then update Project, The discovery is back to the SE1.6 version, I think it must be in the POM definition of this Java version, look at the pom file, found the compilation plug-in definition of version 1.6, code:

<plugin>
<artifactId>maven-compiler-plugin</artifactId>
<configuration>
   <source>1.6</source>
   <target>1.6</target>
</configuration>
</ Plugin>

So it would be nice to change the compiled version to 1.7.

<plugin>
<artifactId>maven-compiler-plugin</artifactId>
<configuration>
<source>1.7</source>
<target>1.7</target>
</configuration>
</ Plugin>

Note: Here is a compilation of plug-ins through the project

Also, define the JDK version of the current project in a general project

   <properties>
         <...> ...<...>
        <java.version>1.8</java.version> ...
        . > ...<...>
    </properties>

This properties property configuration is typically configured after the <parent> tag, and if you refer to your company's framework, you should have a defined version within the framework that you don't need to introduce, and, in short, set as needed. The settings can then be introduced in the compilation plug-in:

<plugin>  
<artifactId>maven-compiler-plugin</artifactId>  
<configuration>  
<source>${java.version}</source>  
<target>${java.version}</target>  
</ Configuration>  
</plugin>