How to write comparator to sort 2D array based on second column using lambda expression

I am working on a sorting 2D-Array problem in Java. I want to sort the array based on the second column in each row such as a[i][1]. I am trying to write a lambda expression to put it in Arrays.sort(a, comparator) to avoid writing a whole class.

Here is what I tried:

Arrays.sort(contests, (int[] num1, int[] num2) -> Integer number1 = num1[1];
   Integer number2 = num2[1];
    return number2.compareTo(number1);
);

I am not sure what is wrong because Java will not give me an exact error message when I run. I know that the first part of a lambda expression is the input, and the second part is comparing. Since .compareTo() only works for objects, that is why I create two Integers. Eclipse keeps telling me to insert; after Integer. Can anyone help me, please? Thank you

The type definitions inside the lambda expression arise from the context, no further type-definitions are needed.
Your example is only working with the values from array contests[1].
Arrays.sort() expects an 1-dimensional array.
If contests is defined as Integer[][] array, then this expression should work for You:

Arrays.sort( contests[1], (num1, num2) -> ( num2.compareTo( num1 ) ) );

To sort both arrays corresponding — Arrays.sort() will not work:

index1 = 0;  // defined as class variable
index2 = 0;  // defined as class variable
Arrays.stream( contests[1] ).map( (n) -> new Integer[] {
    contests[0][index1], contests[1][index1++]
} ).sorted( (arr1,arr2) -> Integer.compare( arr2[1], arr1[1] ) )
.forEach( (arr) -> {
  contests[0][index2] = arr[0];
  contests[1][index2++] = arr[1];
} );

One way is to pair the corresponding values (same index) of contests[0] with contests[1] and map these arrays to the contest[1] values.
After sorting write the values back in the forEach loop.