core: fix class imports

jadx-core/src/main/java/jadx/core/codegen/ClassGen.java

@@ -379,12 +379,17 @@ public class ClassGen {
 			if (classInfo.getPackage().equals(useCls.getPackage()) && !classInfo.isInner()) {
 				return shortName;
 			}
-			if (classInfo.getPackage().equals(useCls.getPackage())) {
-				fullName = classInfo.getNameWithoutPackage();
+			// don't add import if class not public (must be accessed using inheritance)
+			ClassNode classNode = cls.dex().resolveClass(classInfo);
+			if (classNode != null && !classNode.getAccessFlags().isPublic()) {
+				return shortName;
 			}
 			if (searchCollision(cls.dex(), useCls, shortName)) {
 				return fullName;
 			}
+			if (classInfo.getPackage().equals(useCls.getPackage())) {
+				fullName = classInfo.getNameWithoutPackage();
+			}
 			for (ClassInfo importCls : imports) {
 				if (!importCls.equals(classInfo)
 						&& importCls.getShortName().equals(shortName)) {

jadx-samples/src/main/java/jadx/samples/TestImports.java

+package jadx.samples;
+
+import jadx.samples.otherpkg.A;
+
+/**
+ * Tests:
+ * - class B not imported
+ */
+public class TestImports extends AbstractTest {
+
+	public class C extends A {
+		public B getB() {
+			return null;
+		}
+	}
+
+	@Override
+	public boolean testRun() {
+		return true;
+	}
+
+	public static void main(String[] args) {
+		new TestImports().testRun();
+	}
+}

jadx-samples/src/main/java/jadx/samples/otherpkg/A.java

+package jadx.samples.otherpkg;
+
+public class A {
+	protected class B {
+
+	}
+}