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With Eclipse Collections, you would use the forEachKeyValue method on the MapIterable interface, which is inherited by the MutableMap and ImmutableMap interfaces and their implementations.

MutableBag<String> result = Bags.mutable.empty();
MutableMap<Integer, String> map = Maps.mutable.of(1, "One", 2, "Two", 3, "Three");
map.forEachKeyValue((key, value) -> result.add(key + value));
Assert.assertEquals(Bags.mutable.of("1One", "2Two", "3Three"), result);

Using an anonymous inner class, you can write the code as follows:

final MutableBag<String> result = Bags.mutable.empty();
MutableMap<Integer, String> map = Maps.mutable.of(1, "One", 2, "Two", 3, "Three");
map.forEachKeyValue(new Procedure2<Integer, String>()
{
    public void value(Integer key, String value)
    {
        result.add(key + value);
    }
});
Assert.assertEquals(Bags.mutable.of("1One", "2Two", "3Three"), result);

Note: I am a committer for Eclipse Collections.

With Eclipse Collections, you would use the forEachKeyValue method on the MapIterable interface, which is inherited by the MutableMap and ImmutableMap interfaces and their implementations.

MutableMap<Integer, String> map = 
    Maps.mutable.of(1, "One", 2, "Two", 3, "Three");

MutableBag<String> result = Bags.mutable.empty();
map.forEachKeyValue((key, value) -> result.add(key + value));

MutableBag<String> expected = Bags.mutable.of("1One", "2Two", "3Three");
Assertions.assertEquals(expected, result);

The reason using forEachKeyValue with Eclipse Collections (EC) Map implementations will be more efficient than using entrySet is because EC Map implementations do not store Map.Entry objects. Using entrySet with EC Map implementations results in Map.Entry objects being generated dynamically. The forEachKeyValue method is able to avoid creating the Map.Entry objects because it can navigate the internal structure of the Map implementations directly. This is a case where there is a benefit of using an internal iterator over an external iterator.

Note: I am a committer for Eclipse Collections.

With Eclipse Collections (formerly GS Collections), you would use the forEachKeyValue method on the MapIterable interface, which is inherited by the MutableMap and ImmutableMap interfaces and their implementations.

final MutableBag<String> result = Bags.mutable.empty();
MutableMap<Integer, String> map = Maps.mutable.of(1, "One", 2, "Two", 3, "Three");
map.forEachKeyValue(new Procedure2<Integer, String>()
{
    public void value(Integer key, String value)
    {
        result.add(key + value);
    }
});
Assert.assertEquals(Bags.mutable.of("1One", "2Two", "3Three"), result);

With Java 8 lambda syntax, you can write the code as follows:

MutableBag<String> result = Bags.mutable.empty();
MutableMap<Integer, String> map = Maps.mutable.of(1, "One", 2, "Two", 3, "Three");
map.forEachKeyValue((key, value) -> result.add(key + value));
Assert.assertEquals(Bags.mutable.of("1One", "2Two", "3Three"), result);

Note: I am a committer for Eclipse Collections.

With Eclipse Collections, you would use the forEachKeyValue method on the MapIterable interface, which is inherited by the MutableMap and ImmutableMap interfaces and their implementations.

MutableBag<String> result = Bags.mutable.empty();
MutableMap<Integer, String> map = Maps.mutable.of(1, "One", 2, "Two", 3, "Three");
map.forEachKeyValue((key, value) -> result.add(key + value));
Assert.assertEquals(Bags.mutable.of("1One", "2Two", "3Three"), result);

Using an anonymous inner class, you can write the code as follows:

final MutableBag<String> result = Bags.mutable.empty();
MutableMap<Integer, String> map = Maps.mutable.of(1, "One", 2, "Two", 3, "Three");
map.forEachKeyValue(new Procedure2<Integer, String>()
{
    public void value(Integer key, String value) 
    {
        result.add(key + value);
    }
});
Assert.assertEquals(Bags.mutable.of("1One", "2Two", "3Three"), result);

Note: I am a committer for Eclipse Collections.

With Eclipse Collections (formerly GS Collections), you would use the forEachKeyValue method on the MapIterable interface, which is inherited by the MutableMap and ImmutableMap interfaces and their implementations.

final MutableBag<String> result = Bags.mutable.empty();
MutableMap<Integer, String> map = Maps.mutable.of(1, "One", 2, "Two", 3, "Three");
map.forEachKeyValue(new Procedure2<Integer, String>()
{
    public void value(Integer key, String value)
    {
        result.add(key + value);
    }
});
Assert.assertEquals(Bags.mutable.of("1One", "2Two", "3Three"), result);

With Java 8 lambda syntax, you can write the code as follows:

MutableBag<String> result = Bags.mutable.empty();
MutableMap<Integer, String> map = Maps.mutable.of(1, "One", 2, "Two", 3, "Three");
map.forEachKeyValue((key, value) -> { result.add(key + value);});
Assert.assertEquals(Bags.mutable.of("1One", "2Two", "3Three"), result);

Note: I am a committer for Eclipse Collections.

With Eclipse Collections (formerly GS Collections), you would use the forEachKeyValue method on the MapIterable interface, which is inherited by the MutableMap and ImmutableMap interfaces and their implementations.

final MutableBag<String> result = Bags.mutable.empty();
MutableMap<Integer, String> map = Maps.mutable.of(1, "One", 2, "Two", 3, "Three");
map.forEachKeyValue(new Procedure2<Integer, String>()
{
    public void value(Integer key, String value)
    {
        result.add(key + value);
    }
});
Assert.assertEquals(Bags.mutable.of("1One", "2Two", "3Three"), result);

With Java 8 lambda syntax, you can write the code as follows:

MutableBag<String> result = Bags.mutable.empty();
MutableMap<Integer, String> map = Maps.mutable.of(1, "One", 2, "Two", 3, "Three");
map.forEachKeyValue((key, value) -> result.add(key + value));
Assert.assertEquals(Bags.mutable.of("1One", "2Two", "3Three"), result);

Note: I am a committer for Eclipse Collections.