Question

If I reference the SnakeYAML jar directly from a test program (see bottom), everything works. If I’m inside my Maven-created project, I get the following output from my unit tests:

java.lang.NoSuchMethodError: java.util.LinkedList.push(Ljava/lang/Object;)V     at org.yaml.snakeyaml.scanner.ScannerImpl.addIndent(ScannerImpl.java:482)     at org.yaml.snakeyaml.scanner.ScannerImpl.fetchBlockEntry(ScannerImpl.java:653)     at org.yaml.snakeyaml.scanner.ScannerImpl.fetchMoreTokens(ScannerImpl.java:268)     at org.yaml.snakeyaml.scanner.ScannerImpl.checkToken(ScannerImpl.java:178)     at org.yaml.snakeyaml.parser.ParserImpl$ParseImplicitDocumentStart.produce(ParserImpl.java:213)     at org.yaml.snakeyaml.parser.ParserImpl.peekEvent(ParserImpl.java:172)     at org.yaml.snakeyaml.parser.ParserImpl.checkEvent(ParserImpl.java:143)     at org.yaml.snakeyaml.parser.ParserImpl.checkEvent(ParserImpl.java:163)     at org.yaml.snakeyaml.composer.Composer.getSingleNode(Composer.java:66)     at org.yaml.snakeyaml.constructor.BaseConstructor.getSingleData(BaseConstructor.java:60)     at org.yaml.snakeyaml.Loader.load(Loader.java:35)     at org.yaml.snakeyaml.Yaml.load(Yaml.java:134) 

Since Maven couldn’t find SnakeYAML in the central repos, I manually installed it into my local repo. In case it matters, I’m on a Mac using SnakeYAML 0.9, and Maven 2.0.9.

Sample YAML File

-      accountCode: foo     accountId: 1     email: [e-mail]     userId: 1 

Working Test Program

import java.io.*; import java.util.*;  import org.yaml.snakeyaml.Yaml;  /**  * Testing SnakeYAML.  *  * @author Hank Gay  */ public final class Foo {     public static void main(final String[] args) throws Exception {         final Yaml yaml = new Yaml();         Reader reader = null;         try {             reader = new FileReader('/tmp/foo.yaml');             System.out.println(yaml.load(reader));         } catch (final FileNotFoundException fnfe) {             System.err.println('We had a problem reading the YAML from the file because we couldn't find the file.' + fnfe);         } finally {             if (null != reader) {                 try {                     reader.close();                 } catch (final IOException ioe) {                     System.err.println('We got the following exception trying to clean up the reader: ' + ioe);                 }             }         }     } } 

Answer 1

Seems like a JDK version issue: LinkedList#push was introduced in Java 6.

Try setting JAVA_HOME to the correct version before running Maven.