Cloning a java LinkedHashMap

Question

What is the best of cloning a LinkedHasMap in Java?

I already tried:

Map<String, Object> clonedMap = new LinkedHashMap<String, Object>(originalMap);

But that didn't work.

Define "didn't work". new Map(map) makes a "shallow" copy - the references are the same. If you mean a "deep" copy (where all keys and values are also cloned) the answer depends entirely on the implementation of the the key and value classes. — Bohemian
– Bohemian ♦, Commented Dec 21, 2011 at 2:00
As Bohemian has said, deep copy is likely what you are after. See here. — threenplusone
– threenplusone, Commented Dec 21, 2011 at 2:03

Alexey Grigorev · Accepted Answer · 2011-12-21 02:23:00Z

1

The easiest way to get a deep copy is to serialize the map and then deserialize it. The faster way is to go thought the whole map, clone each key/value and put it to a new map.

In case you need a shallow copy - your snippet does that correctly.

answered Dec 21, 2011 at 2:23

Alexey Grigorev

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1 Comment

Ravi Wallau Over a year ago

Although serialization is a simple solution, if you want something automatic, I'd rather use reflection. But even better is to have all your cloneable classes implement the Cloneable interface (docs.oracle.com/javase/6/docs/api/java/lang/Cloneable.html).

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