diff --git a/README.md b/README.md
index 690d99c..352f349 100644
--- a/README.md
+++ b/README.md
@@ -16,7 +16,7 @@ java2js can translate simple Java programs to JavaScript and runs them using a J
 | Double      | Exception     | Float     |
 | Integer     | Long          | Short     |
 | String      | StringBuilder | System    |
-| Thread      | Throwable     |           |
+| Thread      |               |           |
 
 | `java.security` |
 | :-------------- |
diff --git a/jdk.js b/jdk.js
index 9d2d381..5e54d23 100755
--- a/jdk.js
+++ b/jdk.js
@@ -66,6 +66,7 @@
 							let names = [
 								'Character',
 								'Double',
+								'Exception',
 								'Float',
 								'Integer',
 								'Long',
@@ -19129,12 +19130,13 @@
 								'nextLong',
 								'nextFloat',
 								'nextDouble'
-							]
+							],
+							Thread: ['sleep']
 						};
 						if (typeof QuintOS != 'undefined') {
 							Object.assign(asyncMethods, {
 								Sprite: ['move'],
-								window: ['alert', 'delay', 'erase', 'eraseRect', 'frame', 'play', 'prompt', 'text', 'textRect']
+								window: ['alert', 'delay', 'eraseRect', 'frame', 'play', 'prompt', 'text', 'textRect']
 							});
 						}
 						if (!asyncMethods.window) asyncMethods.window = [];
diff --git a/jdk/java/lang/Exception.js b/jdk/java/lang/Exception.js
index e69de29..18cf4ac 100755
--- a/jdk/java/lang/Exception.js
+++ b/jdk/java/lang/Exception.js
@@ -0,0 +1,13 @@
+jdk.imports['java.lang.Exception'].load = async () => {
+	// TODO: should accept a PrintStream or PrintWriter
+	Error.prototype.printStackTrace = function (p) {
+		log(this.stack);
+	};
+	Error.prototype.getStackTrace = function () {
+		return this.stack;
+	};
+	Error.prototype.getMessage = function () {
+		return this.message;
+	};
+	jdk.java.lang.Exception = Error;
+};
diff --git a/jdk/java/lang/Thread.js b/jdk/java/lang/Thread.js
index 88bcbaa..81b7dd1 100755
--- a/jdk/java/lang/Thread.js
+++ b/jdk/java/lang/Thread.js
@@ -1,8 +1,9 @@
 jdk.imports['java.lang.Thread'].load = async () => {
-	class Thread {
-		async sleep(millis) {
-			await setTimeout(millis);
-		}
-	}
+	class Thread {}
+	Thread.sleep = (millis) => {
+		return new Promise((resolve) => {
+			setTimeout(resolve, millis);
+		});
+	};
 	jdk.java.lang.Thread = Thread;
 };
diff --git a/jdk/java/lang/Throwable.js b/jdk/java/lang/Throwable.js
deleted file mode 100755
index e69de29..0000000
diff --git a/jdk/java/util/Scanner.js b/jdk/java/util/Scanner.js
index 73fc37e..41a52c4 100755
--- a/jdk/java/util/Scanner.js
+++ b/jdk/java/util/Scanner.js
@@ -25,37 +25,40 @@ jdk.imports['java.util.Scanner'].load = async () => {
 			// if pattern is string
 			return this.in.stream.slice(this.in.mark).includes(pattern);
 		}
-		async hasNextLine() {
+		hasNextLine() {
 			return this.hasNext('\n');
 		}
-		async nextLine() {
-			return await this.next(/.*\n/);
+		nextLine() {
+			return this.next(/.*/);
 		}
 		async next(pattern) {
 			while (this._loading || !(await this.hasNext(pattern))) {
-				await new Promise((done) => setTimeout(() => done(), 100));
+				await new Promise((resolve) => setTimeout(resolve, 100));
 			}
 			let buf = this.in.stream.slice(this.in.mark);
 			let substr = buf.match(pattern)[0];
 			let start = buf.indexOf(substr);
 			let end = buf.indexOf('\n');
+			if (end == -1) {
+				throw 'NoSuchElementException: No ' + pattern.toString() + ' found in buffer ' + buf;
+			}
 			this.in.read(end - start + 1);
-			return buf.slice(start, end);
+			return buf.slice(start, substr.length);
 		}
-		async nextShort() {
-			return await this.nextInt();
+		nextShort() {
+			return this.nextInt();
 		}
 		async nextInt() {
-			return Number(await this.next(/\d+\D/));
+			return Number(await this.next(/\d+/));
 		}
-		async nextLong() {
-			return await this.nextInt();
+		nextLong() {
+			return this.nextInt();
 		}
 		async nextFloat() {
-			return Number(await this.next(/[0-9\.]+[^0-9\.]/));
+			return Number(await this.next(/[0-9\.]+/));
 		}
-		async nextDouble() {
-			return await this.nextFloat();
+		nextDouble() {
+			return this.nextFloat();
 		}
 		close() {}
 	}
diff --git a/package.json b/package.json
index bc23b27..87d0395 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
 	"name": "java2js",
-	"version": "1.2.5",
+	"version": "1.2.6",
 	"description": "Converts Java to JavaScript and runs it with a JS JDK",
 	"main": "jdk.js",
 	"scripts": {