9012-vscode-java-debug-error:

Issues this PR solves:
1) vscode-java-debug invokes vscode.window.registerTerminalLinkProvider upon extension activation. This method was not implemented in Theia - added it but implementation itself seems like an entire PR and don't know if it is wanted in this PR.
2) after crossing issue #1, second problem was that JDTUtils threw exception when receiving file changed event where URI scheme was user_storage - illegal schema name (_)

Signed-off-by: Dan Arad <dan.arad@sap.com>

packages/plugin-ext/src/plugin/plugin-context.ts

@@ -432,6 +432,9 @@ export function createAPIFactory(
             createInputBox(): theia.InputBox {
                 return quickOpenExt.createInputBox(plugin);
             },
+            registerTerminalLinkProvider(provider: theia.TerminalLinkProvider): void {
+                /* NOOP */
+            },
             get activeColorTheme(): theia.ColorTheme {
                 return themingExt.activeColorTheme;
             },

packages/plugin/src/theia.d.ts

@@ -2871,6 +2871,71 @@ declare module '@theia/plugin' {
         setDimensions?(dimensions: TerminalDimensions): void;
     }
 
+    /**
+     * Provides information on a line in a terminal in order to provide links for it.
+     */
+    // copied from https://github.com/microsoft/vscode/blob/bd20a720fba05f87ddb53c11c6af66936fd88a55/src/vs/vscode.d.ts#L5563-L5576
+    export interface TerminalLinkContext {
+        /**
+         * This is the text from the unwrapped line in the terminal.
+         */
+        line: string;
+
+        /**
+         * The terminal the link belongs to.
+         */
+        terminal: Terminal;
+    }
+
+    /**
+     * A provider that enables detection and handling of links within terminals.
+     */
+    // copied from https://github.com/microsoft/vscode/blob/bd20a720fba05f87ddb53c11c6af66936fd88a55/src/vs/vscode.d.ts#L5578-L5597
+
+    export interface TerminalLinkProvider<T extends TerminalLink = TerminalLink> {
+        /**
+         * Provide terminal links for the given context. Note that this can be called multiple times
+         * even before previous calls resolve, make sure to not share global objects (eg. `RegExp`)
+         * that could have problems when asynchronous usage may overlap.
+         * @param context Information about what links are being provided for.
+         * @param token A cancellation token.
+         * @return A list of terminal links for the given line.
+         */
+        provideTerminalLinks(context: TerminalLinkContext, token: CancellationToken): ProviderResult<T[]>;
+
+        /**
+         * Handle an activated terminal link.
+         * @param link The link to handle.
+         */
+        handleTerminalLink(link: T): ProviderResult<void>;
+    }
+
+    /**
+     * A link on a terminal line.
+     */
+    // copied from https://github.com/microsoft/vscode/blob/bd20a720fba05f87ddb53c11c6af66936fd88a55/src/vs/vscode.d.ts#L5599-L5621
+    export interface TerminalLink {
+        /**
+         * The start index of the link on [TerminalLinkContext.line](#TerminalLinkContext.line].
+         */
+        startIndex: number;
+
+        /**
+         * The length of the link on [TerminalLinkContext.line](#TerminalLinkContext.line]
+         */
+        length: number;
+
+        /**
+         * The tooltip text when you hover over this link.
+         *
+         * If a tooltip is provided, is will be displayed in a string that includes instructions on
+         * how to trigger the link, such as `{0} (ctrl + click)`. The specific instructions vary
+         * depending on OS, user settings, and localization.
+         */
+        tooltip?: string;
+    }
+
+
     /**
      * A type of mutation that can be applied to an environment variable.
      */
@@ -3964,6 +4029,15 @@ declare module '@theia/plugin' {
          */
         export function createInputBox(): InputBox;
 
+
+        /**
+         * Register provider that enables the detection and handling of links within the terminal.
+         * @param provider The provider that provides the terminal links.
+         * @return Disposable that unregisters the provider.
+         */
+        // copied from https://github.com/microsoft/vscode/blob/e790b931385d72cf5669fcefc51cdf65990efa5d/src/vs/vscode.d.ts#L8302-8307
+        export function registerTerminalLinkProvider(provider: TerminalLinkProvider): void;
+
         /**
          * The currently active color theme as configured in the settings. The active
          * theme can be changed via the `workbench.colorTheme` setting.

packages/preferences/src/browser/preferences-json-schema-contribution.ts

@@ -23,7 +23,7 @@ import { PreferenceConfigurations } from '@theia/core/lib/browser/preferences/pr
 import { PreferenceScope } from '@theia/core/lib/browser';
 
 const PREFERENCE_URI_PREFIX = 'vscode://schemas/settings/';
-const USER_STORAGE_PREFIX = 'user_storage:/';
+const USER_STORAGE_PREFIX = 'user-storage:/';
 
 @injectable()
 export class PreferencesJsonSchemaContribution implements JsonSchemaContribution {

packages/userstorage/src/browser/user-storage-uri.ts

@@ -16,4 +16,4 @@
 
 import URI from '@theia/core/lib/common/uri';
 
-export const UserStorageUri = new URI('user_storage:/user');
+export const UserStorageUri = new URI('user-storage:/user');

packages/workspace/src/browser/workspace-uri-contribution.spec.ts

@@ -79,7 +79,7 @@ describe('WorkspaceUriLabelProviderContribution class', () => {
 
     describe('canHandle()', () => {
         it('should return 0 if the passed in argument is not a FileStat or URI with the "file" scheme', () => {
-            expect(labelProvider.canHandle(new URI('user_storage:settings.json'))).eq(0);
+            expect(labelProvider.canHandle(new URI('user-storage:settings.json'))).eq(0);
             expect(labelProvider.canHandle({ uri: 'file:///home/settings.json' })).eq(0);
         });