Predicate class breaks maven-scr plugin while build - maven

Question

I just added a custom predicate class to my project and the maven build just broke with this error. Do I need to add some more dependencies ?
[ERROR] Failed to execute goal org.apache.felix:maven-scr-plugin:1.21.0:scr (generate-scr-descriptor) on project data-providers: Execution generate-scr-descriptor of goal org.apache.felix:maven-scr-plugin:1.21.0:scr failed: An API incompatibility was encountered while executing org.apache.felix:maven-scr-plugin:1.21.0:scr: java.lang.VerifyError: Constructor must call super() or this() before return
[ERROR] Exception Details:
[ERROR] Location:
[ERROR] com/day/cq/search/eval/AbstractPredicateEvaluator.<init>()V #1: return
[ERROR] Reason:
[ERROR] Error exists in the bytecode
[ERROR] Bytecode:
[ERROR] 0x0000000: 2ab1
[ERROR]
[ERROR] -----------------------------------------------------
[ERROR] realm = plugin>org.apache.felix:maven-scr-plugin:1.21.0
[ERROR] strategy = org.codehaus.plexus.classworlds.strategy.SelfFirstStrategy
[ERROR] urls[0] = file:/C:/Users/rmahna/.m2/repository/org/apache/felix/maven-scr-plugin/1.21.0/maven-scr-plugin-1.21.0.jar
[ERROR] urls[1] = file:/C:/Users/rmahna/.m2/repository/org/apache/maven/maven-archiver/2.2/maven-archiver-2.2.jar
[ERROR] urls[2] = file:/C:/Users/rmahna/.m2/repository/junit/junit/3.8.1/junit-3.8.1.jar
[ERROR] urls[3] = file:/C:/Users/rmahna/.m2/repository/org/codehaus/plexus/plexus-archiver/1.0-alpha-7/plexus-archiver-1.0-alpha-7.jar
[ERROR] urls[4] = file:/C:/Users/rmahna/.m2/repository/org/apache/felix/org.apache.felix.scr.generator/1.13.0/org.apache.felix.scr.generator-1.13.0.jar
[ERROR] urls[5] = file:/C:/Users/rmahna/.m2/repository/org/ow2/asm/asm-all/5.0.2/asm-all-5.0.2.jar
[ERROR] urls[6] = file:/C:/Users/rmahna/.m2/repository/org/osgi/org.osgi.core/4.2.0/org.osgi.core-4.2.0.jar
[ERROR] urls[7] = file:/C:/Users/rmahna/.m2/repository/org/osgi/org.osgi.compendium/4.2.0/org.osgi.compendium-4.2.0.jar
[ERROR] urls[8] = file:/C:/Users/rmahna/.m2/repository/org/sonatype/plexus/plexus-build-api/0.0.7/plexus-build-api-0.0.7.jar
[ERROR] urls[9] = file:/C:/Users/rmahna/.m2/repository/org/codehaus/plexus/plexus-utils/1.5.8/plexus-utils-1.5.8.jar
[ERROR] Number of foreign imports: 1
[ERROR] import: Entry[import from realm ClassRealm[project>com.kpmg.cmi.bundles:data-providers:2.0.4, parent: ClassRealm[maven.api, parent: null]]]
[ERROR]
[ERROR] -----------------------------------------------------
My sample Java class is below. I've removed the business logic but even this exact file causes the error.
package my.project.custom.predicates;
import java.util.Comparator;
import javax.jcr.query.Row;
import org.apache.felix.scr.annotations.Component;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import com.day.cq.search.Predicate;
import com.day.cq.search.eval.AbstractPredicateEvaluator;
import com.day.cq.search.eval.EvaluationContext;
#Component(metatype =false, factory="com.day.cq.search.eval.PredicateEvaluator/mypredicate_eval")
public class MyCustomPredicate extends AbstractPredicateEvaluator {
private static final Logger log = LoggerFactory.getLogger(MyCustomPredicate.class);
public static final String MY_PROPERTY = "my_property";
#Override
public boolean includes(Predicate predicate, Row row, EvaluationContext context) {
if(predicate.hasNonEmptyValue(MY_PROPERTY)){
return true;
}
return super.includes(predicate, row, context);
}
#Override
public String getXPathExpression(Predicate predicate, EvaluationContext context) {
if(!predicate.hasNonEmptyValue(MY_PROPERTY)){
return null;
}
/**
* Some generic string comparisons and processing
*/
return super.getXPathExpression(predicate, context);
}
#Override
public Comparator<Row> getOrderByComparator(final Predicate predicate, final EvaluationContext context) {
return new Comparator<Row>() {
public int compare(Row r1, Row r2) {
String[] property1;
String[] property2;
try {
log.info("inside try method");
//lots of string comparisons
} catch (Exception e) {
log.error(e.getMessage());
e.printStackTrace();
}
return 1;
}
};
}
}

Answer 1

I see that you're using the maven-scr-plugin. This plugin has been entirely replaced by standard annotations for the last two releases of the OSGi specification and is now in maintenance mode. My recommendation would be to use the standard annotations instead. The standard annotations are very similar in their use, and will be processed by tools such as the bnd-maven-plugin or maven-bundle-plugin. You are almost certainly already using one of these plugins - the current version (at time of writing) for both plugins is 3.5.0. I would recommend using this version if you need to process Java 8 or Java 9 byte code.
The resulting file will look like this:
package my.project.custom.predicates;
import java.util.Comparator;
import javax.jcr.query.Row;
import org.osgi.service.component.annotations.Component;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import com.day.cq.search.Predicate;
import com.day.cq.search.eval.AbstractPredicateEvaluator;
import com.day.cq.search.eval.EvaluationContext;
#Component
public class MyCustomPredicate extends AbstractPredicateEvaluator {
// Your implementation in here
}