org.drools.RuntimeDroolsException: Unable to load dialect 'org.drools.rule.builder.dialect.java.JavaDialectConfiguration:java'
at org.drools.compiler.PackageBuilderConfiguration.addDialect(PackageBuilderConfiguration.java:160)
at org.drools.compiler.PackageBuilderConfiguration.buildDialectConfigurationMap(PackageBuilderConfiguration.java:146)
at org.drools.compiler.PackageBuilderConfiguration.init(PackageBuilderConfiguration.java:121)
at org.drools.compiler.PackageBuilderConfiguration.<init>(PackageBuilderConfiguration.java:98)
at org.drools.compiler.PackageBuilder.<init>(PackageBuilder.java:124)
at org.drools.compiler.PackageBuilder.<init>(PackageBuilder.java:86)
at com.sample.DecisionTableTest.readDecisionTable(DecisionTableTest.java:58)
at com.sample.DecisionTableTest.main(DecisionTableTest.java:35)
Caused by: java.lang.RuntimeException: The Eclipse JDT Core jar is not in the classpath
at org.drools.rule.builder.dialect.java.JavaDialectConfiguration.setCompiler(JavaDialectConfiguration.java:91)
at org.drools.rule.builder.dialect.java.JavaDialectConfiguration.init(JavaDialectConfiguration.java:52)
at org.drools.compiler.PackageBuilderConfiguration.addDialect(PackageBuilderConfiguration.java:156)
... 7 more
主要是缺少一个jar包：org.eclipse.jdt.core_3.6.0.v_A58.jar而引起的。(注意根据Drool的版本不同该包的名称也会不同.)
在Eclipse或者MyEclipse的plugins目录下面。
Good luck.