Implement Lock and ReentrantLock APIs (#4344)

google-labs-jules[bot] · web-flow · commit b799800c2711 · 2025-12-24T18:28:59.000+02:00
* Implement Lock and ReentrantLock APIs in JavaAPI

Implemented `java.util.concurrent.locks.Lock` and `java.util.concurrent.locks.ReentrantLock` interfaces and classes in `vm/JavaAPI`.
Added `java.util.concurrent.TimeUnit`.
Updated `java.lang.Thread` with `interrupt0`, `sleep(long, int)` and updated `join` implementation.
Added integration tests in `vm/tests` to verify locking behavior using the BytecodeTranslator.

* Implement Lock and ReentrantLock APIs in vm/JavaAPI

- Added `java.util.concurrent.locks.Lock` and `java.util.concurrent.locks.ReentrantLock`.
- Added `java.util.concurrent.TimeUnit`.
- Updated `java.lang.Thread` with `interrupt0`, `sleep(long, int)` and improved `join` logic.
- Created `vm/tests/src/test/java/com/codename1/tools/translator/LockIntegrationTest.java` to verify concurrency primitives using ByteCodeTranslator integration tests.
- Provided native stubs for missing JavaSE methods in the test environment to ensure linker success.

* 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.

* 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.

* 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.

* 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.
- Implemented `java_lang_Thread_interrupt0__` and `java_lang_Thread_isInterrupted` in `vm/ByteCodeTranslator/src/nativeMethods.m` to resolve iOS linker errors.
- Added `interrupted` field to `ThreadLocalData` struct in `cn1_globals.h`.

---------

Co-authored-by: google-labs-jules[bot] &lt;161369871+google-labs-jules[bot]@users.noreply.github.com&gt;
diff --git a/vm/ByteCodeTranslator/src/cn1_globals.h b/vm/ByteCodeTranslator/src/cn1_globals.h
@@ -789,6 +789,7 @@ struct ThreadLocalData {
     char* utf8Buffer;
     int utf8BufferSize;
     JAVA_BOOLEAN threadKilled;      // we don't expect to see this in the GC
+    JAVA_BOOLEAN interrupted;
 };
 
 //#define BLOCK_FOR_GC() while(threadStateData->threadBlockedByGC) { usleep(500); }
diff --git a/vm/ByteCodeTranslator/src/nativeMethods.m b/vm/ByteCodeTranslator/src/nativeMethods.m
@@ -1090,6 +1090,7 @@ JAVA_INT java_lang_Object_hashCode___R_int(CODENAME_ONE_THREAD_STATE, JAVA_OBJEC
         i->threadBlockedByGC = JAVA_FALSE;
         i->threadActive = JAVA_FALSE;
         i->threadKilled = JAVA_FALSE;
+        i->interrupted = JAVA_FALSE;
         
         i->currentThreadObject = 0;
         
@@ -1461,6 +1462,40 @@ JAVA_LONG java_lang_Thread_getNativeThreadId___R_long(CODENAME_ONE_THREAD_STATE)
     return currentThreadId();
 }
 
+JAVA_VOID java_lang_Thread_interrupt0__(CODENAME_ONE_THREAD_STATE, JAVA_OBJECT me) {
+    lockCriticalSection();
+    for(int i=0; i<NUMBER_OF_SUPPORTED_THREADS; i++) {
+        struct ThreadLocalData* d = allThreads[i];
+        if(d && d->currentThreadObject == me) {
+            d->interrupted = JAVA_TRUE;
+            break;
+        }
+    }
+    unlockCriticalSection();
+}
+
+JAVA_BOOLEAN java_lang_Thread_isInterrupted___boolean_R_boolean(CODENAME_ONE_THREAD_STATE, JAVA_OBJECT me, JAVA_BOOLEAN clear) {
+    JAVA_BOOLEAN ret = JAVA_FALSE;
+    // optimization: checking current thread
+    if(threadStateData->currentThreadObject == me) {
+        ret = threadStateData->interrupted;
+        if(clear) threadStateData->interrupted = JAVA_FALSE;
+        return ret;
+    }
+
+    lockCriticalSection();
+    for(int i=0; i<NUMBER_OF_SUPPORTED_THREADS; i++) {
+        struct ThreadLocalData* d = allThreads[i];
+        if(d && d->currentThreadObject == me) {
+            ret = d->interrupted;
+            if(clear) d->interrupted = JAVA_FALSE;
+            break;
+        }
+    }
+    unlockCriticalSection();
+    return ret;
+}
+
 JAVA_DOUBLE java_lang_StringToReal_parseDblImpl___java_lang_String_int_R_double(CODENAME_ONE_THREAD_STATE, JAVA_OBJECT s, JAVA_INT e) {
     int length = java_lang_String_length___R_int(threadStateData, s);
     JAVA_ARRAY arrayData = (JAVA_ARRAY)java_lang_String_toCharNoCopy___R_char_1ARRAY(threadStateData, s);
diff --git a/vm/JavaAPI/src/java/lang/Thread.java b/vm/JavaAPI/src/java/lang/Thread.java
@@ -122,8 +122,21 @@ public final int getPriority(){
      * Interrupts this thread. In an implementation conforming to the CLDC Specification, this operation is not required to cancel or clean up any pending I/O operations that the thread may be waiting for.
      */
     public void interrupt(){
+        interrupt0();
     }
 
+    private native void interrupt0();
+
+    public static boolean interrupted() {
+        return currentThread().isInterrupted(true);
+    }
+
+    public boolean isInterrupted() {
+        return isInterrupted(false);
+    }
+
+    private native boolean isInterrupted(boolean clearInterrupted);
+
     /**
      * Tests if this thread is alive. A thread is alive if it has been started and has not yet died.
      */
@@ -135,12 +148,46 @@ public final boolean isAlive(){
      * Waits for this thread to die.
      */
     public final void join() throws java.lang.InterruptedException{
-        // not very efficient but we don't use this method much...
-        while(alive) {
-            sleep(30);
+        join(0);
+    }
+
+    public final synchronized void join(long millis) throws java.lang.InterruptedException {
+        long base = System.currentTimeMillis();
+        long now = 0;
+
+        if (millis < 0) {
+            throw new IllegalArgumentException("timeout value is negative");
+        }
+
+        if (millis == 0) {
+            while (isAlive()) {
+                wait(0);
+            }
+        } else {
+            while (isAlive()) {
+                long delay = millis - now;
+                if (delay <= 0) {
+                    break;
+                }
+                wait(delay);
+                now = System.currentTimeMillis() - base;
+            }
         }
     }
 
+    public final synchronized void join(long millis, int nanos) throws java.lang.InterruptedException {
+        if (millis < 0) {
+            throw new IllegalArgumentException("timeout value is negative");
+        }
+        if (nanos < 0 || nanos > 999999) {
+            throw new IllegalArgumentException("nanosecond timeout value out of range");
+        }
+        if (nanos >= 500000 || (nanos != 0 && millis == 0)) {
+            millis++;
+        }
+        join(millis);
+    }
+
     /**
      * Invoked from native code...
      */
@@ -155,7 +202,10 @@ private void runImpl(long tid) {
             t.printStackTrace();
         }
         activeThreads--;
-        alive = false;
+        synchronized(this) {
+            alive = false;
+            notifyAll();
+        }
     }
     
     /**
@@ -183,6 +233,19 @@ public final void setPriority(int newPriority){
      */
     public static native void sleep(long millis) throws java.lang.InterruptedException;
 
+    public static void sleep(long millis, int nanos) throws java.lang.InterruptedException {
+        if (millis < 0) {
+            throw new IllegalArgumentException("timeout value is negative");
+        }
+        if (nanos < 0 || nanos > 999999) {
+            throw new IllegalArgumentException("nanosecond timeout value out of range");
+        }
+        if (nanos >= 500000 || (nanos != 0 && millis == 0)) {
+            millis++;
+        }
+        sleep(millis);
+    }
+
     /**
      * Causes this thread to begin execution; the Java Virtual Machine calls the run method of this thread.
      * The result is that two threads are running concurrently: the current thread (which returns from the call to the start method) and the other thread (which executes its run method).
diff --git a/vm/JavaAPI/src/java/util/concurrent/TimeUnit.java b/vm/JavaAPI/src/java/util/concurrent/TimeUnit.java
@@ -0,0 +1,143 @@
+package java.util.concurrent;
+
+public enum TimeUnit {
+    NANOSECONDS(0),
+    MICROSECONDS(1),
+    MILLISECONDS(2),
+    SECONDS(3),
+    MINUTES(4),
+    HOURS(5),
+    DAYS(6);
+
+    private final int index;
+    TimeUnit(int i) { index = i; }
+
+    static final long C0 = 1L;
+    static final long C1 = C0 * 1000L;
+    static final long C2 = C1 * 1000L;
+    static final long C3 = C2 * 1000L;
+    static final long C4 = C3 * 60L;
+    static final long C5 = C4 * 60L;
+    static final long C6 = C5 * 24L;
+
+    static final long MAX = Long.MAX_VALUE;
+
+    static long x(long d, long m, long over) {
+        if (d >  over) return Long.MAX_VALUE;
+        if (d < -over) return Long.MIN_VALUE;
+        return d * m;
+    }
+
+    public long convert(long sourceDuration, TimeUnit sourceUnit) {
+        switch(this) {
+            case NANOSECONDS: return sourceUnit.toNanos(sourceDuration);
+            case MICROSECONDS: return sourceUnit.toMicros(sourceDuration);
+            case MILLISECONDS: return sourceUnit.toMillis(sourceDuration);
+            case SECONDS: return sourceUnit.toSeconds(sourceDuration);
+            case MINUTES: return sourceUnit.toMinutes(sourceDuration);
+            case HOURS: return sourceUnit.toHours(sourceDuration);
+            case DAYS: return sourceUnit.toDays(sourceDuration);
+            default: throw new RuntimeException("Unknown unit");
+        }
+    }
+
+    public long toNanos(long d) {
+        if (this == NANOSECONDS) return d;
+        if (this == MICROSECONDS) return x(d, C1/C0, MAX/(C1/C0));
+        if (this == MILLISECONDS) return x(d, C2/C0, MAX/(C2/C0));
+        if (this == SECONDS) return x(d, C3/C0, MAX/(C3/C0));
+        if (this == MINUTES) return x(d, C4/C0, MAX/(C4/C0));
+        if (this == HOURS) return x(d, C5/C0, MAX/(C5/C0));
+        return x(d, C6/C0, MAX/(C6/C0));
+    }
+
+    public long toMicros(long d) {
+        if (this == NANOSECONDS) return d / (C1/C0);
+        if (this == MICROSECONDS) return d;
+        if (this == MILLISECONDS) return x(d, C2/C1, MAX/(C2/C1));
+        if (this == SECONDS) return x(d, C3/C1, MAX/(C3/C1));
+        if (this == MINUTES) return x(d, C4/C1, MAX/(C4/C1));
+        if (this == HOURS) return x(d, C5/C1, MAX/(C5/C1));
+        return x(d, C6/C1, MAX/(C6/C1));
+    }
+
+    public long toMillis(long d) {
+        if (this == NANOSECONDS) return d / (C2/C0);
+        if (this == MICROSECONDS) return d / (C2/C1);
+        if (this == MILLISECONDS) return d;
+        if (this == SECONDS) return x(d, C3/C2, MAX/(C3/C2));
+        if (this == MINUTES) return x(d, C4/C2, MAX/(C4/C2));
+        if (this == HOURS) return x(d, C5/C2, MAX/(C5/C2));
+        return x(d, C6/C2, MAX/(C6/C2));
+    }
+
+    public long toSeconds(long d) {
+        if (this == NANOSECONDS) return d / (C3/C0);
+        if (this == MICROSECONDS) return d / (C3/C1);
+        if (this == MILLISECONDS) return d / (C3/C2);
+        if (this == SECONDS) return d;
+        if (this == MINUTES) return x(d, C4/C3, MAX/(C4/C3));
+        if (this == HOURS) return x(d, C5/C3, MAX/(C5/C3));
+        return x(d, C6/C3, MAX/(C6/C3));
+    }
+
+    public long toMinutes(long d) {
+        if (this == NANOSECONDS) return d / (C4/C0);
+        if (this == MICROSECONDS) return d / (C4/C1);
+        if (this == MILLISECONDS) return d / (C4/C2);
+        if (this == SECONDS) return d / (C4/C3);
+        if (this == MINUTES) return d;
+        if (this == HOURS) return x(d, C5/C4, MAX/(C5/C4));
+        return x(d, C6/C4, MAX/(C6/C4));
+    }
+
+    public long toHours(long d) {
+        if (this == NANOSECONDS) return d / (C5/C0);
+        if (this == MICROSECONDS) return d / (C5/C1);
+        if (this == MILLISECONDS) return d / (C5/C2);
+        if (this == SECONDS) return d / (C5/C3);
+        if (this == MINUTES) return d / (C5/C4);
+        if (this == HOURS) return d;
+        return x(d, C6/C5, MAX/(C6/C5));
+    }
+
+    public long toDays(long d) {
+        if (this == NANOSECONDS) return d / (C6/C0);
+        if (this == MICROSECONDS) return d / (C6/C1);
+        if (this == MILLISECONDS) return d / (C6/C2);
+        if (this == SECONDS) return d / (C6/C3);
+        if (this == MINUTES) return d / (C6/C4);
+        if (this == HOURS) return d / (C6/C5);
+        return d;
+    }
+
+    private int excessNanos(long d, long m) {
+        if (this == NANOSECONDS) return (int)(d - (m*C2));
+        if (this == MICROSECONDS) return (int)((d*C1) - (m*C2));
+        return 0;
+    }
+
+    public void timedWait(Object obj, long timeout) throws InterruptedException {
+        if (timeout > 0) {
+            long ms = toMillis(timeout);
+            int ns = excessNanos(timeout, ms);
+            obj.wait(ms, ns);
+        }
+    }
+
+    public void timedJoin(Thread thread, long timeout) throws InterruptedException {
+        if (timeout > 0) {
+            long ms = toMillis(timeout);
+            int ns = excessNanos(timeout, ms);
+            thread.join(ms, ns);
+        }
+    }
+
+    public void sleep(long timeout) throws InterruptedException {
+        if (timeout > 0) {
+            long ms = toMillis(timeout);
+            int ns = excessNanos(timeout, ms);
+            Thread.sleep(ms, ns);
+        }
+    }
+}
diff --git a/vm/JavaAPI/src/java/util/concurrent/locks/Condition.java b/vm/JavaAPI/src/java/util/concurrent/locks/Condition.java
@@ -0,0 +1,20 @@
+package java.util.concurrent.locks;
+
+import java.util.concurrent.TimeUnit;
+import java.util.Date;
+
+public interface Condition {
+    void await() throws InterruptedException;
+
+    void awaitUninterruptibly();
+
+    long awaitNanos(long nanosTimeout) throws InterruptedException;
+
+    boolean await(long time, TimeUnit unit) throws InterruptedException;
+
+    boolean awaitUntil(Date deadline) throws InterruptedException;
+
+    void signal();
+
+    void signalAll();
+}
diff --git a/vm/JavaAPI/src/java/util/concurrent/locks/Lock.java b/vm/JavaAPI/src/java/util/concurrent/locks/Lock.java
@@ -0,0 +1,17 @@
+package java.util.concurrent.locks;
+
+import java.util.concurrent.TimeUnit;
+
+public interface Lock {
+    void lock();
+
+    void lockInterruptibly() throws InterruptedException;
+
+    boolean tryLock();
+
+    boolean tryLock(long time, TimeUnit unit) throws InterruptedException;
+
+    void unlock();
+
+    Condition newCondition();
+}
diff --git a/vm/JavaAPI/src/java/util/concurrent/locks/ReentrantLock.java b/vm/JavaAPI/src/java/util/concurrent/locks/ReentrantLock.java
diff --git a/vm/tests/src/test/java/com/codename1/tools/translator/LockIntegrationTest.java b/vm/tests/src/test/java/com/codename1/tools/translator/LockIntegrationTest.java
