core: remove synthetic constructors

jadx-core/src/main/java/jadx/core/dex/visitors/ClassModifier.java

@@ -9,6 +9,7 @@ import jadx.core.dex.instructions.IndexInsnNode;
 import jadx.core.dex.instructions.InsnType;
 import jadx.core.dex.instructions.args.InsnArg;
 import jadx.core.dex.instructions.args.RegisterArg;
+import jadx.core.dex.instructions.mods.ConstructorInsn;
 import jadx.core.dex.nodes.BlockNode;
 import jadx.core.dex.nodes.ClassNode;
 import jadx.core.dex.nodes.FieldNode;
@@ -26,7 +27,12 @@ public class ClassModifier extends AbstractVisitor {
 		for (ClassNode inner : cls.getInnerClasses()) {
 			visit(inner);
 		}
-
+		if (cls.getAccessFlags().isSynthetic()
+				&& cls.getFields().isEmpty()
+				&& cls.getMethods().isEmpty()) {
+			cls.getAttributes().add(AttributeFlag.DONT_GENERATE);
+			return false;
+		}
 		removeSyntheticFields(cls);
 		removeSyntheticMethods(cls);
 		removeEmptyMethods(cls);
@@ -110,6 +116,18 @@ public class ClassModifier extends AbstractVisitor {
 					it.remove();
 				}
 			}
+
+			// remove synthetic constructor for inner non-static classes
+			if (af.isSynthetic() && af.isConstructor() && mth.getBasicBlocks().size() == 2) {
+				List<InsnNode> insns = mth.getBasicBlocks().get(0).getInstructions();
+				if (insns.size() == 1 && insns.get(0).getType() == InsnType.CONSTRUCTOR) {
+					ConstructorInsn constr = (ConstructorInsn) insns.get(0);
+					if (constr.isThis() && mth.getArguments(false).size() >= 1) {
+						mth.removeFirstArgument();
+						mth.getAttributes().add(AttributeFlag.DONT_GENERATE);
+					}
+				}
+			}
 		}
 	}
 

jadx-core/src/test/java/jadx/tests/internal/TestInnerClass2.java

+package jadx.tests.internal;
+
+import jadx.api.InternalJadxTest;
+import jadx.core.dex.nodes.ClassNode;
+
+import java.util.Timer;
+import java.util.TimerTask;
+
+import org.junit.Test;
+
+import static org.hamcrest.CoreMatchers.containsString;
+import static org.hamcrest.CoreMatchers.not;
+import static org.junit.Assert.assertThat;
+
+public class TestInnerClass2 extends InternalJadxTest {
+
+	public static class TestCls {
+		private static class TerminateTask extends TimerTask {
+			@Override
+			public void run() {
+				System.err.println("Test timed out");
+			}
+		}
+
+		public void test() {
+			new Timer().schedule(new TerminateTask(), 1000);
+		}
+	}
+
+	@Test
+	public void test() {
+		ClassNode cls = getClassNode(TestCls.class);
+		String code = cls.getCode().toString();
+
+		assertThat(code, containsString("new Timer().schedule(new TerminateTask(), 1000);"));
+		assertThat(code, not(containsString("synthetic")));
+		assertThat(code, not(containsString("this")));
+		assertThat(code, not(containsString("null")));
+		assertThat(code, not(containsString("AnonymousClass")));
+	}
+}