Eclipse throwing errors for maven compile phase?

Question

Projects are not able to execute two life cycle phases of maven life cycle mapping:

1. compiler:compile
2. compiler: testcompile

Following are errors in eclipse:

1. CoreException: Could not calculate build plan: Plugin org.apache.maven.plugins:maven-compiler-plugin:2.5.1 or one of its dependencies could not be resolved: Failed to read artifact descriptor for org.apache.maven.plugins:maven-compiler-plugin:jar:2.5.1: ArtifactResolutionException: Failure to transfer org.apache.maven.plugins:maven-compiler-plugin:pom:2.5.1 from http://repo.maven.apache.org/maven2 was cached in the local repository, resolution will not be reattempted until the update interval of central has elapsed or updates are forced. Original error: Could not transfer artifact org.apache.maven.plugins:maven-compiler-plugin:pom:2.5.1 from/to central (http://repo.maven.apache.org/maven2): repo.maven.apache.org
   pom.xml /ex line 1 Maven Project Build Lifecycle Mapping Problem

2. Plugin execution not covered by lifecycle configuration: org.apache.maven.plugins:maven-compiler-plugin:2.5.1:compile (execution: default-compile, phase: compile) pom.xml
   /ex line 1 Maven Project Build Lifecycle Mapping Problem

3. Plugin execution not covered by lifecycle configuration: org.apache.maven.plugins:maven-compiler-plugin:2.5.1:testCompile (execution: default-testCompile, phase: test-compile)
   pom.xml /ex line 1 Maven Project Build Lifecycle Mapping Problem

Answer 1

In eclipse goto windows->preferences->maven->user setting

point user settings textbox to setting.xml in %M2_HOME%\conf

Answer 2

if its not working still then you need to add plugins in the POM.xml and update project

<build>
    <plugins>
        <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-surefire-plugin</artifactId>
                <version>2.20</version>
                <configuration>
                     <suiteXmlFiles>
                            <suiteXmlFile>testng.xml</suiteXmlFile>
                     </suiteXmlFiles>
                </configuration>
             </plugin>
             <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-compiler-plugin</artifactId>
            <version>3.6.2</version>
            <configuration>
                <source>1.8</source>
                <target>1.8</target>
        </configuration>
        </plugin>
    </plugins>
</build>