Implement Lock and ReentrantLock APIs in vm/JavaAPI

- Added `java.util.concurrent.locks.Lock` interface.
- Added `java.util.concurrent.locks.ReentrantLock` implementation.
- Added `java.util.concurrent.locks.Condition` interface.
- Added `java.util.concurrent.TimeUnit` enum.
- Updated `java.lang.Thread` with `interrupt0`, `sleep`, `join` support.
- Added `LockIntegrationTest` in `vm/tests` to verify bytecode translation of new APIs.
- Fixed spin loop in `ReentrantLock.lock()` when interrupted.
- Fixed integration test setup to avoid conflicting native stubs.

Author: google-labs-jules[bot]

vm/JavaAPI/src/java/util/concurrent/locks/ReentrantLock.java

@@ -23,15 +23,19 @@ public void lock() {
                 holdCount++;
                 return;
             }
+            boolean interrupted = false;
             while (owner != null) {
                 try {
                     sync.wait();
                 } catch (InterruptedException e) {
-                     Thread.currentThread().interrupt();
+                     interrupted = true;
                 }
             }
             owner = current;
             holdCount = 1;
+            if (interrupted) {
+                Thread.currentThread().interrupt();
+            }
         }
     }
 

vm/tests/src/test/java/com/codename1/tools/translator/LockIntegrationTest.java

@@ -199,6 +199,12 @@ private void writeMockJavaClasses(Path sourceDir) throws Exception {
         // java.util.Date
         Files.write(util.resolve("Date.java"), "package java.util; public class Date { public long getTime() { return 0; } }".getBytes(StandardCharsets.UTF_8));
 
+        // java.util.Objects
+        Files.write(util.resolve("Objects.java"), ("package java.util;\n" +
+                "public class Objects {\n" +
+                "    public static <T> T requireNonNull(T obj) { if (obj == null) throw new NullPointerException(); return obj; }\n" +
+                "}\n").getBytes(StandardCharsets.UTF_8));
+
         // java.util.concurrent.TimeUnit
         Files.write(concurrent.resolve("TimeUnit.java"), ("package java.util.concurrent;\n" +
                 "public class TimeUnit {\n" +