The code explains itself:

```
class Solution {
public int findLength(int[] A, int[] B) {
if(A == null||B == null) return 0;
int m = A.length;
int n = B.length;
int max = 0;
//dp[i][j] is the length of longest common subarray ending with nums[i] and nums[j]
int[][] dp = new int[m + 1][n + 1];
for(int i = 0;i <= m;i++){
for(int j = 0;j <= n;j++){
if(i == 0 || j == 0){
dp[i][j] = 0;
}
else{
if(A[i - 1] == B[j - 1]){
dp[i][j] = 1 + dp[i - 1][j - 1];
max = Math.max(max,dp[i][j]);
}
}
}
}
return max;
}
}
```

Hope it helps!