Write down the syntax to return the first occurrence of 'a' in the word "applications".

Write down the syntax to replace the word "old" with the word "new" in a given String st = "old is always old"

Predict the output of the following Java program snippet:

String str = "Computer Applications" + 1 + 0;
System.out.println("Understanding" + str);

Predict the output of the following Java program snippet:

String n1 = "46", n2 = "64";
int total = Integer.parseInt(n1) + Integer.parseInt(n2);
System.out.println("The sum of " + "46 " + "and" + " 64" + " is " + total);