The root of a jar+file or zip uri should only exist if the underlying file exist

src/org/rascalmpl/uri/jar/JarFileResolver.java

@@ -39,10 +39,19 @@ public class JarFileResolver  {
             .expireAfterAccess(10, TimeUnit.MINUTES) // 10 minutes after last access, drop it
             .softValues().build();
 
-    protected CompressedFSTree getFileHierchyCache(ISourceLocation jar) {
+
+    private File jarFile(ISourceLocation jar) {
+        return new File(jar.getPath());
+    }
+
+    protected CompressedFSTree getFileHierchyCache(ISourceLocation jar) throws IOException {
         try {
-            final File jarFile = new File(jar.getPath());
-            return fsCache.get(URIUtil.changeQuery(jar, "mod=" + jarFile.lastModified()), j -> new JarFileTree(jarFile));
+            var jarFile = jarFile(jar);
+            var lastModified = jarFile.lastModified();
+            if (lastModified == 0) {
+                throw new FileNotFoundException("The file " + jar + "does not exist or is a directory");
+            }
+            return fsCache.get(URIUtil.changeQuery(jar, "mod=" + lastModified), j -> new JarFileTree(jarFile));
         }
         catch (URISyntaxException e) {
             throw new RuntimeException(e);
@@ -60,21 +69,21 @@ public InputStream getInputStream(ISourceLocation jar, String path) throws IOExc
         return jarFile.getInputStream(jarEntry);
     }
 
-    public boolean exists(ISourceLocation jar, String path) {
+    public boolean exists(ISourceLocation jar, String path) throws IOException {
         if (path == null || path.isEmpty() || path.equals("/")) {
-            return true;
+            return jarFile(jar).isFile();
         }
         return getFileHierchyCache(jar).exists(path);
     }
 
-    public boolean isDirectory(ISourceLocation jar, String path) {
+    public boolean isDirectory(ISourceLocation jar, String path) throws IOException {
         if (!path.endsWith("/")) {
             path = path + "/";
         }
         return getFileHierchyCache(jar).isDirectory(path);
     }
 
-    public boolean isFile(ISourceLocation jar, String path) {
+    public boolean isFile(ISourceLocation jar, String path) throws IOException {
         return getFileHierchyCache(jar).isFile(path);
     }
 

src/org/rascalmpl/uri/jar/JarInputStreamResolver.java

@@ -32,7 +32,7 @@ public JarInputStreamResolver(URIResolverRegistry registry) {
     }
 
 	@Override
-    protected CompressedFSTree getFileHierchyCache(ISourceLocation jarLocation) {
+    protected CompressedFSTree getFileHierchyCache(ISourceLocation jarLocation) throws IOException {
         try {
             final ISourceLocation lookupKey = URIUtil.changeQuery(jarLocation, "mod=" + CTX.lastModified(jarLocation));
             return fsCache.get(lookupKey, j -> {
@@ -44,7 +44,7 @@ protected CompressedFSTree getFileHierchyCache(ISourceLocation jarLocation) {
                 }
             });
         }
-        catch (URISyntaxException | IOException e) {
+        catch (URISyntaxException e) {
             throw new RuntimeException(e);
         }
     }

src/org/rascalmpl/uri/zip/ZipFileResolver.java

@@ -38,10 +38,17 @@ public class ZipFileResolver  {
             .expireAfterAccess(10, TimeUnit.MINUTES) // 10 minutes after last access, drop it
             .softValues().build();
 
-    protected CompressedFSTree getFileHierchyCache(ISourceLocation zip) {
+    private File zipFile(ISourceLocation zip) {
+        return new File(zip.getPath());
+    }
+    protected CompressedFSTree getFileHierchyCache(ISourceLocation zip) throws IOException {
         try {
-            final File zipFile = new File(zip.getPath());
-            return fsCache.get(URIUtil.changeQuery(zip, "mod=" + zipFile.lastModified()), j -> new ZipFileTree(zipFile));
+            var zipFile = zipFile(zip);
+            var lastModified = zipFile.lastModified();
+            if (lastModified == 0) {
+                throw new FileNotFoundException("File " + zip + " not found");
+            }
+            return fsCache.get(URIUtil.changeQuery(zip, "mod=" + lastModified), j -> new ZipFileTree(zipFile));
         }
         catch (URISyntaxException e) {
             throw new RuntimeException(e);
@@ -59,21 +66,21 @@ public InputStream getInputStream(ISourceLocation zip, String path) throws IOExc
         return zipFile.getInputStream(zipEntry);
     }
 
-    public boolean exists(ISourceLocation zip, String path) {
+    public boolean exists(ISourceLocation zip, String path)  throws IOException {
         if (path == null || path.isEmpty() || path.equals("/")) {
-            return true;
+            return zipFile(zip).isFile();
         }
         return getFileHierchyCache(zip).exists(path);
     }
 
-    public boolean isDirectory(ISourceLocation zip, String path) {
+    public boolean isDirectory(ISourceLocation zip, String path)  throws IOException{
         if (!path.endsWith("/")) {
             path = path + "/";
         }
         return getFileHierchyCache(zip).isDirectory(path);
     }
 
-    public boolean isFile(ISourceLocation zip, String path) {
+    public boolean isFile(ISourceLocation zip, String path) throws IOException {
         return getFileHierchyCache(zip).isFile(path);
     }