From b5e530f971498e190e377bcb38f2dec23b13a365 Mon Sep 17 00:00:00 2001
From: Andrey Loskutov <loskutov@gmx.de>
Date: Wed, 20 Feb 2019 17:57:35 +0100
Subject: [PATCH] Bug 544578 - don't iterate over all projects if JRE was already found

While searching for the matching JRE we don't need to loop over all
projects if we had a match. With N projects in the workspace and ~50
modules we have in the JRE, we can save ~ N x 25 x 25 compares.

Change-Id: I611e5e499ae07f380dfea7a4b092c809bdf9f87e
Signed-off-by: Andrey Loskutov <loskutov@gmx.de>
---

diff --git a/org.eclipse.jdt.launching/launching/org/eclipse/jdt/internal/launching/JavaSourceLookupUtil.java b/org.eclipse.jdt.launching/launching/org/eclipse/jdt/internal/launching/JavaSourceLookupUtil.java
index cbbbe50..dbb4bdd 100644
--- a/org.eclipse.jdt.launching/launching/org/eclipse/jdt/internal/launching/JavaSourceLookupUtil.java
+++ b/org.eclipse.jdt.launching/launching/org/eclipse/jdt/internal/launching/JavaSourceLookupUtil.java
@@ -230,21 +230,30 @@
 				IJavaProject jp = jps[i];
 				IProject p = jp.getProject();
 				if (p.isOpen()) {
-					IPackageFragmentRoot[] allRoots = jp.getPackageFragmentRoots();
-					for (int j = 0; j < allRoots.length; j++) {
-						IPackageFragmentRoot root = allRoots[j];
-						if (root.getPath().equals(entryPath) && isSourceAttachmentEqual(root, entry)) {
-							PackageFragmentRootSourceContainer container = new PackageFragmentRootSourceContainer(root);
-							if (!containers.contains(container)) {
-								containers.add(container);
-								found = true;
+					try {
+						IPackageFragmentRoot[] allRoots = jp.getPackageFragmentRoots();
+						for (int j = 0; j < allRoots.length; j++) {
+							IPackageFragmentRoot root = allRoots[j];
+							if (root.getPath().equals(entryPath) && isSourceAttachmentEqual(root, entry)) {
+								PackageFragmentRootSourceContainer container = new PackageFragmentRootSourceContainer(root);
+								if (!containers.contains(container)) {
+									containers.add(container);
+									found = true;
+								}
 							}
 						}
+					} catch (JavaModelException e) {
+						LaunchingPlugin.log(e);
+						found = false;
+					}
+					if (found) {
+						// JRE module containers can't be spread over *multiple* projects,
+						// we have either all or nothing, no need to search other projects.
+						break;
 					}
 				}
 			}
-		}
-		catch (JavaModelException e) {
+		} catch (JavaModelException e) {
 			LaunchingPlugin.log(e);
 		}