Easy to understand , simple java solution, 0ms 100%
\nclass Solution {\n    public int[] getConcatenation(int[] nums) {\n     int[] ans=new int[nums.length*2];\n        \n        for(int i=0;i<nums.length;i++){\n
```\nclass Solution {\n    public int[] getConcatenation(int[] nums) {\n     int[] ans=new int[nums.length*2];\n        \n        for(int i=0;i<nums.length;i++){\n            ans[i]=nums[i];\n            \n            ans[i+nums.length]=nums[i];\n        }\n        return ans;\n    }\n}\n```
['Array', 'Java']