isDone check in NativeFuture.dispose, try/finally for finalizers, some rewriting of stack tester context transaction management.

bindings/java/src-completable/main/com/apple/foundationdb/Cluster.java

@@ -59,10 +59,14 @@ public class Cluster extends DefaultDisposableImpl implements Disposable {
 
 	@Override
 	protected void finalize() throws Throwable {
+		try {
 			checkUndisposed("Cluster");
 			dispose();
+		}
+		finally {
 			super.finalize();
 		}
+	}
 
 	/**
 	 * Creates a connection to a specific database on an <i>FDB</i> cluster.

bindings/java/src-completable/main/com/apple/foundationdb/FDBDatabase.java

@@ -101,10 +101,14 @@ class FDBDatabase extends DefaultDisposableImpl implements Database, Disposable,
 
 	@Override
 	protected void finalize() throws Throwable {
+		try {
 			checkUndisposed("Database");
 			dispose();
+		}
+		finally {
 			super.finalize();
 		}
+	}
 
 	@Override
 	public Transaction createTransaction(Executor e) {

bindings/java/src-completable/main/com/apple/foundationdb/FDBTransaction.java

@@ -555,10 +555,14 @@ class FDBTransaction extends DefaultDisposableImpl implements Disposable, Transa
 
 	@Override
 	protected void finalize() throws Throwable {
+		try {
 			checkUndisposed("Transaction");
 			dispose();
+		}
+		finally {
 			super.finalize();
 		}
+	}
 
 	@Override
 	protected void disposeInternal(long cPtr) {

bindings/java/src-completable/main/com/apple/foundationdb/LocalityUtil.java

@@ -227,11 +227,11 @@ public class LocalityUtil {
 					System.err.println("DisposableAsyncIterator not disposed (getBoundaryKeys)");
 				}
 			}
-			catch(Exception e) {}
+			finally {
-
 				super.finalize();
 			}
 		}
+	}
 
 	private static Charset ASCII = Charset.forName("US-ASCII");
 	static byte[] keyServersForKey(byte[] key) {

bindings/java/src-completable/main/com/apple/foundationdb/NativeFuture.java

@@ -99,9 +99,11 @@ abstract class NativeFuture<T> extends CompletableFuture<T> implements Disposabl
 
 		if(ptr != 0) {
 			Future_dispose(ptr);
+			if(!isDone()) {
 				completeExceptionally(new IllegalStateException("Future has been disposed"));
 			}
 		}
+	}
 
 	@Override
 	public boolean cancel(boolean mayInterruptIfRunning) {
@@ -130,7 +132,6 @@ abstract class NativeFuture<T> extends CompletableFuture<T> implements Disposabl
 		return cPtr;
 	}
 
-
 	private native void Future_registerCallback(long cPtr, Runnable callback);
 	private native void Future_blockUntilReady(long cPtr);
 	private native boolean Future_isReady(long cPtr);

bindings/java/src-completable/test/com/apple/foundationdb/test/AsyncStackTester.java

@@ -418,7 +418,7 @@ public class AsyncStackTester {
 								inst.context.newTransaction(oldTr); // Other bindings allow reuse of non-retryable transactions, so we need to emulate that behavior.
 							}
 							else {
-								inst.context.updateCurrentTransaction(oldTr, tr);
+								inst.setTransaction(oldTr, tr);
 							}
 						})
 						.thenApply(v -> null);

bindings/java/src-completable/test/com/apple/foundationdb/test/Context.java

@@ -101,21 +101,20 @@ abstract class Context implements Runnable {
 	}
 
 	public synchronized void updateCurrentTransaction(Transaction tr) {
-		Context.transactionRefCounts.putIfAbsent(tr, new AtomicInteger(1));
+		Context.transactionRefCounts.computeIfAbsent(tr, x -> new AtomicInteger(1));
 		releaseTransaction(Context.transactionMap.put(this.trName, tr));
 	}
 
 	public synchronized boolean updateCurrentTransaction(Transaction oldTr, Transaction newTr) {
-		Context.transactionRefCounts.putIfAbsent(newTr, new AtomicInteger(1));
 		if(Context.transactionMap.replace(this.trName, oldTr, newTr)) {
+			AtomicInteger count = Context.transactionRefCounts.computeIfAbsent(newTr, x -> new AtomicInteger(0));
+			count.incrementAndGet();
 			releaseTransaction(oldTr);
 			return true;
 		}
-		else {
+
-			Context.transactionRefCounts.remove(newTr);
 		return false;
 	}
-	}
 
 	public void newTransaction() {
 		Transaction tr = db.createTransaction();
@@ -131,12 +130,8 @@ abstract class Context implements Runnable {
 
 	public synchronized void switchTransaction(byte[] trName) {
 		this.trName = ByteArrayUtil.printable(trName);
-		Transaction tr = db.createTransaction();
+		Transaction tr = Context.transactionMap.computeIfAbsent(this.trName, x -> db.createTransaction());
-		Context.transactionRefCounts.put(tr, new AtomicInteger(1));
+		Context.transactionRefCounts.computeIfAbsent(tr, x -> new AtomicInteger(1));
-		Transaction previousTr = Context.transactionMap.putIfAbsent(this.trName, tr);
-		if(previousTr != null) {
-			releaseTransaction(tr);
-		}
 	}
 
 	abstract void executeOperations() throws Throwable;

bindings/java/src-completable/test/com/apple/foundationdb/test/Instruction.java

@@ -86,6 +86,20 @@ class Instruction extends Stack {
 		}
 	}
 
+	void setTransaction(Transaction oldTr, Transaction newTr) {
+		if(!isDatabase) {
+			context.updateCurrentTransaction(oldTr, newTr);
+
+			this.tr = context.getCurrentTransaction();
+			if(isSnapshot) {
+				readTr = this.tr.snapshot();
+			}
+			else {
+				readTr = tr;
+			}
+		}
+	}
+
 	void releaseTransaction() {
 		context.releaseTransaction(this.tr);
 	}