Maven build Compilation error : Failed to execute goal org.apache.maven.plugins:maven-compiler-plugin:3.1:compile (default-compile) on project Maven

Question

I have a maven project forked and cloned from a git repo onto my eclipse. It is build on Java 8. The first thing i do is perform a

mvn clean install 

But I get following failure message:

[INFO] Scanning for projects... [INFO]                                                                          [INFO] ------------------------------------------------------------------------ [INFO] Building Maven 0.0.1-SNAPSHOT [INFO] ------------------------------------------------------------------------ [INFO]  [INFO] --- maven-clean-plugin:2.5:clean (default-clean) @ Maven --- [INFO] Deleting /Users/vshukla/git/Prism/target [INFO]  [INFO] --- maven-resources-plugin:2.6:resources (default-resources) @ Maven --- [WARNING] Using platform encoding (UTF-8 actually) to copy filtered resources, i.e. build is platform dependent! [INFO] skip non existing resourceDirectory /Users/vshukla/git/Prism/src/main/resources [INFO]  [INFO] --- maven-compiler-plugin:3.1:compile (default-compile) @ Maven --- [INFO] Changes detected - recompiling the module! [WARNING] File encoding has not been set, using platform encoding UTF-8, i.e. build is platform dependent! [INFO] Compiling 66 source files to /Users/vshukla/git/Prism/target/classes [INFO] ------------------------------------------------------------- [ERROR] COMPILATION ERROR :  [INFO] ------------------------------------------------------------- [ERROR] /Users/vshukla/git/Prism/src/main/java/PrenPost/scanUtility.java:[54,52] diamond operator is not supported in -source 1.5   (use -source 7 or higher to enable diamond operator) [ERROR] /Users/vshukla/git/Prism/src/main/java/main/AppUtility.java:[87,86] diamond operator is not supported in -source 1.5   (use -source 7 or higher to enable diamond operator) [ERROR] /Users/vshukla/git/Prism/src/main/java/PrenPost/ComparisionUtility.java:[58,52] diamond operator is not supported in -source 1.5   (use -source 7 or higher to enable diamond operator) [INFO] 3 errors  [INFO] ------------------------------------------------------------- [INFO] ------------------------------------------------------------------------ [INFO] BUILD FAILURE [INFO] ------------------------------------------------------------------------ [INFO] Total time: 1.266 s [INFO] Finished at: 2017-03-01T12:11:27+05:30 [INFO] Final Memory: 13M/309M [INFO] ------------------------------------------------------------------------ [ERROR] Failed to execute goal org.apache.maven.plugins:maven-compiler-plugin:3.1:compile (default-compile) on project Maven: Compilation failure: Compilation failure: [ERROR] /Users/vshukla/git/Prism/src/main/java/PrenPost/scanUtility.java:[54,52] diamond operator is not supported in -source 1.5 [ERROR] (use -source 7 or higher to enable diamond operator) [ERROR] /Users/vshukla/git/Prism/src/main/java/main/AppUtility.java:[87,86] diamond operator is not supported in -source 1.5 [ERROR] (use -source 7 or higher to enable diamond operator) [ERROR] /Users/vshukla/git/Prism/src/main/java/PrenPost/ComparisionUtility.java:[58,52] diamond operator is not supported in -source 1.5 [ERROR] (use -source 7 or higher to enable diamond operator) [ERROR] -> [Help 1] [ERROR]  [ERROR] To see the full stack trace of the errors, re-run Maven with the -e switch. [ERROR] Re-run Maven using the -X switch to enable full debug logging. [ERROR]  [ERROR] For more information about the errors and possible solutions, please read the following articles: [ERROR] [Help 1]   http://cwiki.apache.org/confluence/display/MAVEN/MojoFailureException 

However, below is the build path details of the project which clearly has JRE - 8 set up:

and the compilation set up:

No matter how many times I build the project, i get the same error. Even after cleaning the project and refreshing it from eclipse doesn't help. Please guide.

UPDATE:

After adding the properties to set maven compiler plugin

<properties>  <maven.compiler.source>1.8</maven.compiler.source>  <maven.compiler.target>1.8</maven.compiler.target> </properties> 

,

am getting the below error:

[INFO] Scanning for projects... [INFO]                                                                          [INFO] ------------------------------------------------------------------------ [INFO] Building Maven 0.0.1-SNAPSHOT [INFO] ------------------------------------------------------------------------ [INFO]  [INFO] --- maven-clean-plugin:2.5:clean (default-clean) @ Maven --- [INFO] Deleting /Users/vshukla/git/Prism/target [INFO]  [INFO] --- maven-resources-plugin:2.6:resources (default-resources) @ Maven --- [WARNING] Using platform encoding (UTF-8 actually) to copy filtered resources, i.e. build is platform dependent! [INFO] skip non existing resourceDirectory /Users/vshukla/git/Prism/src/main/resources [INFO]  [INFO] --- maven-compiler-plugin:3.1:compile (default-compile) @ Maven --- [INFO] Changes detected - recompiling the module! [WARNING] File encoding has not been set, using platform encoding UTF-8, i.e. build is platform dependent! [INFO] Compiling 66 source files to /Users/vshukla/git/Prism/target/classes [INFO] ------------------------------------------------------------- [WARNING] COMPILATION WARNING :  [INFO] ------------------------------------------------------------- [WARNING] /Users/vshukla/git/Prism/src/main/java/main/MainUITabbed.java: /Users/vshukla/git/Prism/src/main/java/main/MainUITabbed.java uses or overrides a deprecated API. [WARNING] /Users/vshukla/git/Prism/src/main/java/main/MainUITabbed.java: Recompile with -Xlint:deprecation for details. [WARNING] /Users/vshukla/git/Prism/src/main/java/main/MainUITabbed.java: Some input files use unchecked or unsafe operations. [WARNING] /Users/vshukla/git/Prism/src/main/java/main/MainUITabbed.java: Recompile with -Xlint:unchecked for details. [INFO] 4 warnings  [INFO] ------------------------------------------------------------- [INFO] ------------------------------------------------------------- [ERROR] COMPILATION ERROR :  [INFO] ------------------------------------------------------------- [ERROR] /Users/vshukla/git/Prism/src/main/java/main/MainUITabbed.java:[26,22] package com.apple.eawt does not exist [ERROR] /Users/vshukla/git/Prism/src/main/java/main/MainUITabbed.java:[93,41] cannot find symbol   symbol: class Application [ERROR] /Users/vshukla/git/Prism/src/main/java/main/MainUITabbed.java:[93,67] cannot find symbol   symbol: variable Application [INFO] 3 errors  [INFO] ------------------------------------------------------------- [INFO] ------------------------------------------------------------------------ [INFO] BUILD FAILURE [INFO] ------------------------------------------------------------------------ [INFO] Total time: 2.591 s [INFO] Finished at: 2017-03-01T13:09:47+05:30 [INFO] Final Memory: 21M/347M [INFO] ------------------------------------------------------------------------ [ERROR] Failed to execute goal org.apache.maven.plugins:maven-compiler-plugin:3.1:compile (default-compile) on project Maven: Compilation failure: Compilation failure: [ERROR] /Users/vshukla/git/Prism/src/main/java/main/MainUITabbed.java:[26,22] package com.apple.eawt does not exist [ERROR] /Users/vshukla/git/Prism/src/main/java/main/MainUITabbed.java:[93,41] cannot find symbol [ERROR] symbol: class Application [ERROR] /Users/vshukla/git/Prism/src/main/java/main/MainUITabbed.java:[93,67] cannot find symbol [ERROR] symbol: variable Application [ERROR] -> [Help 1] [ERROR]  [ERROR] To see the full stack trace of the errors, re-run Maven with the -e switch. [ERROR] Re-run Maven using the -X switch to enable full debug logging. [ERROR]  [ERROR] For more information about the errors and possible solutions, please read the following articles: [ERROR] [Help 1] http://cwiki.apache.org/confluence/display/MAVEN/MojoFailureException 

And here is the code snippet giving the compilation error from MainUITabbed class:

import com.apple.eawt.Application; public static void main(String[] args) {     EventQueue.invokeLater(new Runnable() {         public void run() {             try {                   Application application = Application.getApplication(); // line 93                  ImageIcon imgicon = new ImageIcon(getClass().getResource(                         "ICON.jpg"));                 Image img = imgicon.getImage();                   application.setDockIconImage(img);                  MainUITabbed frame = new MainUITabbed();                 frame.setVisible(true);             } catch (Exception e) {                 e.printStackTrace();              }         }     }); } 

Answer 1

The error occurred because the code is not for the default compiler used there. Paste this code in effective POM before the root element ends, after declaring dependencies, to change the compiler used. Adjust version as you need.

<dependencies> ... </dependencies> <build>     <plugins>         <plugin>             <groupId>org.apache.maven.plugins</groupId>             <artifactId>maven-compiler-plugin</artifactId>             <configuration>                 <source>1.8</source>                 <target>1.8</target>             </configuration>         </plugin>     </plugins> </build> 

Answer 2

I don't think that IDE is relevant here. After all you're running a Maven and Maven doesn't have a source that will allow to compile the diamond operators. So, I think you should configure maven-compiler-plugin itself.

You can read about this here. But in general try to add the following properties:

<properties>  <maven.compiler.source>1.8</maven.compiler.source>  <maven.compiler.target>1.8</maven.compiler.target> </properties> 

and see whether it compiles now in Maven only.