fix: prevent ConcurrentModificationException in CancellationSupport.c…

…ancel

Signed-off-by: Fred Bricon <[email protected]>

src/main/java/com/redhat/devtools/intellij/lsp4ij/internal/CancellationSupport.java

@@ -10,10 +10,10 @@
  ******************************************************************************/
 package com.redhat.devtools.intellij.lsp4ij.internal;
 
-import java.util.ArrayList;
 import java.util.List;
 import java.util.concurrent.CancellationException;
 import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.CopyOnWriteArrayList;
 
 import org.eclipse.lsp4j.jsonrpc.CancelChecker;
 
@@ -32,7 +32,7 @@ public class CancellationSupport implements CancelChecker {
 	private boolean cancelled;
 
 	public CancellationSupport() {
-		this.futuresToCancel = new ArrayList<CompletableFuture<?>>();
+		this.futuresToCancel = new CopyOnWriteArrayList<>();
 		this.cancelled = false;
 	}
 
@@ -45,7 +45,7 @@ public <T> CompletableFuture<T> execute(CompletableFuture<T> future) {
 	 * Cancel all LSP requests.
 	 */
 	public void cancel() {
-		if (cancelled == true) {
+		if (cancelled) {
 			return;
 		}
 		this.cancelled = true;