Java/Maven can't compile simple code - string

Question

This very simple code simply won't compile. I'm not exactly a Java pro but I'm pretty sure this is standard stuff and should just work!
String fields = "a,b,c";
String[] fields_array = fields.split(',');
Won't compile
mvn test clean
cannot find symbol symbol : method split(char)
location: class java.lang.String
pom.xml
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>com.example</groupId>
<artifactId>simple-service</artifactId>
<packaging>jar</packaging>
<version>1.0-SNAPSHOT</version>
<name>simple-service</name>
<dependencyManagement>
<dependencies>
<dependency>
<groupId>org.glassfish.jersey</groupId>
<artifactId>jersey-bom</artifactId>
<version>${jersey.version}</version>
<type>pom</type>
<scope>import</scope>
</dependency>
</dependencies>
</dependencyManagement>
<dependencies>
<dependency>
<groupId>org.glassfish.jersey.containers</groupId>
<artifactId>jersey-container-grizzly2-http</artifactId>
</dependency>
<dependency>
<groupId>org.glassfish.jersey.media</groupId>
<artifactId>jersey-media-moxy</artifactId>
</dependency>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.9</version>
<scope>test</scope>
</dependency>
<dependency>
<groupId>commons-lang</groupId>
<artifactId>commons-lang</artifactId>
<version>2.3</version>
</dependency>
<dependency>
<groupId>org.glassfish.jersey.core</groupId>
<artifactId>jersey-client</artifactId>
<scope>test</scope>
</dependency>
<dependency>
<groupId>de.abas.ceks</groupId>
<artifactId>jedp</artifactId>
<version>1.0</version>
</dependency>
<dependency>
<groupId>de.abas.jfop</groupId>
<artifactId>base</artifactId>
<version>1.0</version>
</dependency>
<dependency>
<groupId>de.abas.eks</groupId>
<artifactId>jfop</artifactId>
<version>1.0</version>
</dependency>
<dependency>
<groupId>de.abas.erp</groupId>
<artifactId>common</artifactId>
<version>1.0</version>
</dependency>
<dependency>
<groupId>net.sourceforge.javautil</groupId>
<artifactId>common</artifactId>
<version>0.0.5</version>
<scope>compile</scope>
</dependency>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>5.1.6</version>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<version>2.5.1</version>
<!-- <inherited>true</inherited> -->
<configuration>
<source>1.6</source>
<target>1.6</target>
</configuration>
</plugin>
<plugin>
<groupId>org.codehaus.mojo</groupId>
<artifactId>exec-maven-plugin</artifactId>
<version>1.2.1</version>
<executions>
<execution>
<goals>
<goal>java</goal>
</goals>
</execution>
</executions>
<configuration>
<mainClass>com.example.Main</mainClass>
</configuration>
</plugin>
</plugins>
</build>
<repositories>
<repository>
<id>javautil</id>
<name>Java Util Repository</name>
<url>http://downloads.sourceforge.net/project/javautil/</url>
</repository>
</repositories>
<properties>
<jersey.version>2.2</jersey.version>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
</properties>
</project>
imports
package com.example;
import javax.ws.rs.GET;
import javax.ws.rs.Path;
import javax.ws.rs.Produces;
import javax.ws.rs.core.MediaType;
import javax.ws.rs.DefaultValue;
import javax.ws.rs.QueryParam;
import de.abas.ceks.jedp.*;
import java.lang.String;

Answer 1

String#split() method takes a String, and ',' is a character. String literals are enclosed in double quotes. You should use:
String[] fields_array = fields.split(",");
PS: You don't need to import classes from java.lang package. That package is by default imported in all Java source files.