From 7c3de8e806fdcdb548db1a23658e838c840fd863 Mon Sep 17 00:00:00 2001
From: Hannes Wellmann <wellmann.hannes1@gmx.net>
Date: Fri, 19 Apr 2024 19:19:05 +0200
Subject: [PATCH] Cache JRT-FileSystem created for JrtFileSystem instances

---
 .../jdt/internal/compiler/util/JRTUtil.java   | 19 ++++++++++++++++---
 1 file changed, 16 insertions(+), 3 deletions(-)

diff --git a/org.eclipse.jdt.core.compiler.batch/src/org/eclipse/jdt/internal/compiler/util/JRTUtil.java b/org.eclipse.jdt.core.compiler.batch/src/org/eclipse/jdt/internal/compiler/util/JRTUtil.java
index 19de8fc6e4b..bce10356e79 100644
--- a/org.eclipse.jdt.core.compiler.batch/src/org/eclipse/jdt/internal/compiler/util/JRTUtil.java
+++ b/org.eclipse.jdt.core.compiler.batch/src/org/eclipse/jdt/internal/compiler/util/JRTUtil.java
@@ -76,6 +76,7 @@ public class JRTUtil {
 	 * Map from JDK home path to ct.sym file (located in /lib in the JDK)
 	 */
 	private static final Map<Path, CtSym> ctSymFiles = new ConcurrentHashMap<>();
+	private static final Map<String, FileSystem> JRT_FILE_SYSTEMS = new ConcurrentHashMap<>();
 
 	static final SoftClassCache classCache = new SoftClassCache();
 
@@ -166,6 +167,20 @@ public static JrtFileSystem getJrtSystem(File image, String release) throws IOEx
 		}
 	}
 
+	static FileSystem getJrtFileSystem(String path) throws IOException {
+		try {
+			return JRT_FILE_SYSTEMS.computeIfAbsent(path, p -> {
+				try {
+					return FileSystems.newFileSystem(JRTUtil.JRT_URI, Map.of("java.home", p)); //$NON-NLS-1$
+				} catch (IOException e) {
+					throw new RuntimeIOException(e);
+				}
+			});
+		} catch (RuntimeIOException e) {
+			throw e.getCause();
+		}
+	}
+
 	/**
 	 * Convenient method to get access to the given archive as a {@link FileSystem}.
 	 * <p>
@@ -531,9 +546,7 @@ public static JrtFileSystem getNewJrtFileSystem(Jdk jdk, String release) throws
 		this.jdk = jdkHome;
 		this.release = release;
 		JRTUtil.MODULE_TO_LOAD = System.getProperty("modules.to.load"); //$NON-NLS-1$
-		HashMap<String, String> env = new HashMap<>();
-		env.put("java.home", this.jdk.path); //$NON-NLS-1$
-		this.fs = FileSystems.newFileSystem(JRTUtil.JRT_URI, env);
+		this.fs = JRTUtil.getJrtFileSystem(this.jdk.path);
 		this.modRoot = this.fs.getPath(JRTUtil.MODULES_SUBDIR);
 		// Set up the root directory where modules are located
 		walkJrtForModules();