Short Approach…
It’s an excellent idea to combine 2 two technologies such as Drools and GWT to build Intelligent Web Applications. But there is a little bit of a problem at the moment to integrate them. Because Drools and GWT include the org.eclipse.jdt classes but with different JDT version. And when you run your application (mvn gwt:run) you will have an error like this:
Unable to parse module: com.google.gwt.user.User java.lang.NoSuchMethodError: org.eclipse.jdt.internal.compiler.CompilationResult.getErrors() [Lorg/eclipse/jdt/core/compiler/IProblem; at com.google.gwt.dev.jdt.AbstractCompiler$ICompilerRequestorImpl. acceptResult(AbstractCompiler.java:213) at org.eclipse.jdt.internal.compiler.Compiler.compile (Compiler.java:417) ...
Solution…
So to solve this problem you need to add an exclusion to your dependecy (that has the Drools-Core dependency) added in your Maven Gwt Application pom.xml. The exclusion in your pom should look like this:
<dependencies> [...] <dependency> <groupId>com.wordpress.nicozan</groupId> <artifactId>dependency-with-drools-core</artifactId> <version>1.0</version> <exclusions> <exclusion> <groupId>org.eclipse.jdt.core.compiler</groupId> <artifactId>ecj</artifactId> </exclusion> </exclusions> </dependency> [...] </dependencies>
Short but helpful 😉