ANTLR is a powerful parser generator for multiple programming languages including Java.

ANTLR contains 2 major modules:

• Runtime - For building and executing parsers/lexers generated in Java.
• Tool (The Parser Generator) - For generating parsers/lexers Java class.

ANTLR Runtime Source Code files are provided in the distribution packge (antlr4-4.10.1.zip). You can download them at ANTLR Website.

You can also browse the source code below:

⏎ org/antlr/v4/runtime/misc/IntegerStack.java

/*
 * Copyright (c) 2012-2017 The ANTLR Project. All rights reserved.
 * Use of this file is governed by the BSD 3-clause license that
 * can be found in the LICENSE.txt file in the project root.
 */
package org.antlr.v4.runtime.misc;

/**
 *
 * @author Sam Harwell
 */
public class IntegerStack extends IntegerList {

	public IntegerStack() {
	}

	public IntegerStack(int capacity) {
		super(capacity);
	}

	public IntegerStack(IntegerStack list) {
		super(list);
	}

	public final void push(int value) {
		add(value);
	}

	public final int pop() {
		return removeAt(size() - 1);
	}

	public final int peek() {
		return get(size() - 1);
	}

}

⏎ org/antlr/v4/runtime/misc/IntegerStack.java

Or download all of them as a single archive file:

File name: antlr-runtime-4.10.1-sources.jar
File size: 308953 bytes
Release date: 2022-04-15
Download 

⇒ ANTLR Tool Source Code

⇐ What Is ANTLR Parser Generator

⇑ Download and Review ANTLR Parser Generator

⇑⇑ FAQ for ANTLR Parser Generator