nullpointerexception - Null Pointer Exception on Array in Java -

the following code returning nullpointerexception in java. can clarify mistake?

public void deposit2() {     bankaccounts[] accounts2 = new bankaccounts[10];     accounts2[3].deposit(); } 

bankaccounts[] accounts2 = new bankaccounts[10]; 

is same as

bankaccounts[] accounts2 = {null, null, null, ... null };  // (10 times) 

you need assign values elements of accounts2 (or, @ least element 3) before attempt dereference them.