Print Maven output on error

Signed-off-by: Juan Manuel Leflet Estrada <jleflete@redhat.com>

external-providers/java-external-provider/pkg/java_external_provider/dependency.go

@@ -162,7 +162,7 @@ func getMavenLocalRepoPath(mvnSettingsFile string) string {
 	}
 
 	// check errors
-	return string(outb.String())
+	return outb.String()
 }
 
 func (p *javaServiceClient) GetDependenciesFallback(ctx context.Context, location string) (map[uri.URI][]*provider.Dep, error) {
@@ -310,7 +310,7 @@ func (p *javaServiceClient) getDependenciesForMaven(_ context.Context) (map[uri.
 	cmd.Dir = moddir
 	mvnOutput, err := cmd.CombinedOutput()
 	if err != nil {
-		return nil, err
+		return nil, fmt.Errorf("maven dependency:tree command failed with error %w, maven output: %s", err, mvnOutput)
 	}
 
 	lines := strings.Split(string(mvnOutput), "\n")

external-providers/java-external-provider/pkg/java_external_provider/provider.go

@@ -275,7 +275,7 @@ func (p *javaProvider) Init(ctx context.Context, log logr.Logger, config provide
 		mvnOutput, err := cmd.CombinedOutput()
 		if err != nil {
 			cancelFunc()
-			return nil, additionalBuiltinConfig, fmt.Errorf("error downloading java artifact %s - %w", mvnUri, err)
+			return nil, additionalBuiltinConfig, fmt.Errorf("error downloading java artifact %s - maven output: %s - with error %w", mvnUri, mvnOutput, err)
 		}
 		downloadedPath := filepath.Join(outputDir,
 			fmt.Sprintf("%s.jar", strings.Join(mvnCoordinatesParts[1:3], "-")))
@@ -686,7 +686,7 @@ func resolveSourcesJarsForMaven(ctx context.Context, log logr.Logger, location,
 	cmd.Dir = location
 	mvnOutput, err := cmd.CombinedOutput()
 	if err != nil {
-		return err
+		return fmt.Errorf("maven downloadSources command failed with error %w, maven output: %s", err, mvnOutput)
 	}
 
 	reader := bytes.NewReader(mvnOutput)