IDEA Maven管理项目的错误整理

摘要：Maven，IDEA

（1）Error:java: Compilation failed: internal java compiler error

• Error:java: Compilation failed: internal java compiler error
  参考https://blog.csdn.net/wo541075754/article/details/82119860

jdk版本问题, 检查Project Structure下Project的Project SDK和Project language level，Modules下Sources下language level，Settings下Java Compiler以及pom是否一致

<plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <version>3.2</version>
                <configuration>
                    <source>1.8</source>
                    <target>1.8</target>
                    <encoding>UTF-8</encoding>
                </configuration>
            </plugin>

（2）新建一个java项目同时支持scala

Libraries或者Global Libraries下设置添加scala sdk

• Exception in thread "main" java.lang.NoClassDefFoundError: scala/Predef$
  在pom.xml中添加

<!-- scala -->
        <dependency>
            <groupId>org.scala-lang</groupId>
            <artifactId>scala-library</artifactId>
            <version>${scala.version}</version>
        </dependency>
        <dependency>
            <groupId>org.scala-lang.modules</groupId>
            <artifactId>scala-xml_2.11</artifactId>
            <version>1.0.6</version>
        </dependency>

在project settings中的SDKs中添加classpath，.m2/repository/org/scala-lang/scala-library/2.11.11/scala-library-2.11.11.jar

（3）maven窗口消失 只剩Ant

菜单栏Help->Find Action(Ctrl+Shift+A),输入Maven projects，点击 Add Maven Projects，或者打开pom.xml，右键Add Maven Projects

（4）打补丁patch

右键项目文件，subversion -> commit directory -> 点击commit的下箭头 -> create patch