Character.toString(...) results in ERROR (compile)

[michael-newsrx]

GWT version: 2.9.0
Browser (with version): Firefox
Operating System: Linux Ubuntu Mate

---

Description

Compiling:

@Override
	public CompletableFuture<SubscriberListResult> loadSubscribers(final String from, final String until) {
		CallbackFuture<SubscriberListResult> cf = new CallbackFuture<>();
		final Token param = state.token();
		REST.withCallback(cf.callback()).call(rest).getSubscribers(
				(from == null || from == "") ? Character.toString(Character.MIN_CODE_POINT) : from,
				(until == null || until == "") ? Character.toString(Character.MAX_CODE_POINT) : until, param);
		return cf.future();
	}

results in:

GET /recompile/gwt
   Job com.newsrx.ButterAdmin_1_12
      starting job: com.newsrx.ButterAdmin_1_12
      binding: locale=default
      binding: user.agent=safari
      Compiling module com.newsrx.ButterAdmin
         Ignored 1 unit with compilation errors in first pass.
Compile with -strict or with -logLevel set to TRACE or DEBUG to see all errors.
         [ERROR] Errors in 'file:/home/michael/git/ButterAdmin/ButterAdmin-client/src/main/java/com/newsrx/client/app/model/ApiImpl.java'
            [ERROR] Line 482: The method toString(Object) from the type Object is not visible
            [ERROR] Line 483: The method toString(Object) from the type Object is not visible
         Tracing compile failure path for type 'com.newsrx.client.app.model.ApiImpl'
            [ERROR] Errors in 'file:/home/michael/git/ButterAdmin/ButterAdmin-client/src/main/java/com/newsrx/client/app/model/ApiImpl.java'
               [ERROR] Line 482: The method toString(Object) from the type Object is not visible
               [ERROR] Line 483: The method toString(Object) from the type Object is not visible

Known workarounds

@Override
	public CompletableFuture<SubscriberListResult> loadSubscribers(final String from, final String until) {
		CallbackFuture<SubscriberListResult> cf = new CallbackFuture<>();
		final Token param = state.token();
		final char minCodePoint = (char) Character.MIN_CODE_POINT;
		final char maxCodePoint = (char) Character.MAX_CODE_POINT;
		REST.withCallback(cf.callback()).call(rest).getSubscribers(
				(from == null || from == "") ? String.valueOf(minCodePoint) : from,
				(until == null || until == "") ? String.valueOf(maxCodePoint) : until, param);
		return cf.future();
	}

[tbroyer]

java.lang.Character#toString(int) is not emulated, only toString(char) (and toString() on instances): http://www.gwtproject.org/doc/latest/RefJreEmulation.html#Package_java_lang

The proper workaround is to use String.valueOf(Character.toChars(Character.MIN_CODE_POINT)) or new String(new int[] { Character.MIN_CODE_POINT }, 0, 1)

Patch welcome, as it shouldn't be too hard to add emulation for that method.