Add all the elements of multiple ArrayList objects into a single ArrayList object

Question

In my case I have 4 ArrayList objects as below:

ArrayList<MyProduct> lstStyle;
ArrayList<MyProduct> 2ndStyle;
ArrayList<MyProduct> 3rdStyle;
ArrayList<MyProduct> 4thStyle;

I want to add all the elements in each ArrayList into a new ArrayList called Style.

ArrayList<MyProduct> Style;

Can I do this without looping each ArrayList?

Konstantin Yovkov · Accepted Answer · 2013-11-26 10:20:52Z

3

Style.addAll(lstStyle);
Style.addAll(2ndStyle);
Style.addAll(3rdStyle);
Style.addAll(4thStyle);

Ofcourse, you need to instantiate all the lists first, otherwise you'll face a NullPointerException.

answered Nov 26, 2013 at 10:20

Konstantin Yovkov

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Comments

shreyansh jogi · Accepted Answer · 2013-11-26 10:21:15Z

3

Collections.addAll(Style, lstStyle, 2ndStyle, 3rdStyle, 34thStyle);

answered Nov 26, 2013 at 10:21

shreyansh jogi

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Collections.addAll adds all of the specified elements to the specified collection. Elements to be added may be specified individually or as an array.

Masudul · Accepted Answer · 2013-11-26 10:32:43Z

0

Use addAll method

ArrayList<MyProduct> Style;

 Style.addAll(lstStyle);
 Style.addAll(2ndStyle);
 Style.addAll(3rdStyle);
 Style.addAll(4thStyle);

answered Nov 26, 2013 at 10:20

Masudul

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