Fix #15199: Exclude JavaDefined Modules from bridge generation.

compiler/src/dotty/tools/dotc/transform/Bridges.scala

@@ -37,7 +37,7 @@ class Bridges(root: ClassSymbol, thisPhase: DenotTransformer)(using Context) {
     override def parents = Array(root.superClass)
 
     override def exclude(sym: Symbol) =
-      !sym.isOneOf(MethodOrModule) || super.exclude(sym)
+      !sym.isOneOf(MethodOrModule) || sym.isAllOf(Module | JavaDefined) || super.exclude(sym)
 
     override def canBeHandledByParent(sym1: Symbol, sym2: Symbol, parent: Symbol): Boolean =
       OverridingPairs.isOverridingPair(sym1, sym2, parent.thisType)

compiler/src/dotty/tools/dotc/typer/Checking.scala

@@ -527,7 +527,7 @@ object Checking {
       fail("Traits cannot have secondary constructors" + addendum)
     checkApplicable(Inline, sym.isTerm && !sym.isOneOf(Mutable | Module))
     checkApplicable(Lazy, !sym.isOneOf(Method | Mutable))
-    if (sym.isType && !sym.is(Deferred))
+    if (sym.isType && !sym.isOneOf(Deferred | JavaDefined))
       for (cls <- sym.allOverriddenSymbols.filter(_.isClass)) {
         fail(CannotHaveSameNameAs(sym, cls, CannotHaveSameNameAs.CannotBeOverridden))
         sym.setFlag(Private) // break the overriding relationship by making sym Private

tests/run/i15199/Child_1.java

@@ -0,0 +1,4 @@
+public class Child_1 extends Parent_1 {
+  public class Inner {
+  }
+}

tests/run/i15199/Parent_1.java

@@ -0,0 +1,4 @@
+public class Parent_1 {
+  public class Inner {
+  }
+}

tests/run/i15199/Test_2.scala

@@ -0,0 +1,5 @@
+class ScalaChild extends Child_1
+
+@main def Test(): Unit =
+  val methods = classOf[ScalaChild].getDeclaredMethods()
+  assert(methods.length == 0, methods.mkString(", "))