https://github.com/eclipse/eclipse-collections/eclipse-collections-api: Eclipse Collections is a collections framework for Java. It has JDK-compatible List, Set and Map implementations with a rich API and set of utility classes that work with any JDK compatible Collections, Arrays, Maps or Strings. The iteration protocol was inspired by the Smalltalk collection framework.
  • Craig P. Motlin
  • Donald Raab
  • Mohammad A. Rezaei
  • Hiroshi Ito
  • Nikhil J. Nanivadekar 
/*
 * Copyright (c) 2017 Goldman Sachs and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * and Eclipse Distribution License v. 1.0 which accompany this distribution.
 * The Eclipse Public License is available at http://www.eclipse.org/legal/epl-v10.html
 * and the Eclipse Distribution License is available at
 * http://www.eclipse.org/org/documents/edl-v10.php.
 */

package org.eclipse.collections.api.factory;

import org.eclipse.collections.api.factory.set.FixedSizeSetFactory;
import org.eclipse.collections.api.factory.set.ImmutableSetFactory;
import org.eclipse.collections.api.factory.set.MutableSetFactory;


This class should be used to create instances of MutableSet, ImmutableSet and FixedSizeSet


Mutable Examples:

MutableSet<String> emptySet = Sets.mutable.empty();
MutableSet<String> setWith = Sets.mutable.with("a", "b", "c");
MutableSet<String> setOf = Sets.mutable.of("a", "b", "c");


Immutable Examples:

ImmutableSet<String> emptySet = Sets.immutable.empty();
ImmutableSet<String> setWith = Sets.immutable.with("a", "b", "c");
ImmutableSet<String> setOf = Sets.immutable.of("a", "b", "c");


FixedSize Examples:

FixedSizeSet<String> emptySet = Sets.fixedSize.empty();
FixedSizeSet<String> setWith = Sets.fixedSize.with("a", "b", "c");
FixedSizeSet<String> setOf = Sets.fixedSize.of("a", "b", "c");



/**
 * This class should be used to create instances of MutableSet, ImmutableSet and FixedSizeSet
 * <p>
 * Mutable Examples:
 *
 * <pre>
 * MutableSet&lt;String&gt; emptySet = Sets.mutable.empty();
 * MutableSet&lt;String&gt; setWith = Sets.mutable.with("a", "b", "c");
 * MutableSet&lt;String&gt; setOf = Sets.mutable.of("a", "b", "c");
 * </pre>
 *
 * Immutable Examples:
 *
 * <pre>
 * ImmutableSet&lt;String&gt; emptySet = Sets.immutable.empty();
 * ImmutableSet&lt;String&gt; setWith = Sets.immutable.with("a", "b", "c");
 * ImmutableSet&lt;String&gt; setOf = Sets.immutable.of("a", "b", "c");
 * </pre>
 *
 * FixedSize Examples:
 *
 * <pre>
 * FixedSizeSet&lt;String&gt; emptySet = Sets.fixedSize.empty();
 * FixedSizeSet&lt;String&gt; setWith = Sets.fixedSize.with("a", "b", "c");
 * FixedSizeSet&lt;String&gt; setOf = Sets.fixedSize.of("a", "b", "c");
 * </pre>
 */
@SuppressWarnings("ConstantNamingConvention")
public final class Sets
{
    public static final ImmutableSetFactory immutable =
            ServiceLoaderUtils.loadServiceClass(ImmutableSetFactory.class);
    public static final MutableSetFactory mutable =
            ServiceLoaderUtils.loadServiceClass(MutableSetFactory.class);
    public static final FixedSizeSetFactory fixedSize =
            ServiceLoaderUtils.loadServiceClass(FixedSizeSetFactory.class);

    private Sets()
    {
        throw new AssertionError("Suppress default constructor for noninstantiability");
    }
}