Type List vs type ArrayList in Java

Almost always List is preferred over ArrayList because, for instance, List can be translated into a LinkedList without affecting the rest of the codebase. If one used ArrayList instead of List, it’s hard to change the ArrayList implementation into a LinkedList one because ArrayList specific methods have been used in the codebase that would also require restructuring. You can read about the List implementations here. You may start with an ArrayList, but soon after discover that … Read more

Calculate average in java

Just some minor modification to your code will do (with some var renaming for clarity) : Note that the loop can also be simplified: Edit: the OP seems to want to use the args array. This seems to be a String array, thus updated the answer accordingly. Update: As zoxqoj correctly pointed out, integer/double overflow is not … Read more

what is Ljava.lang.String;@

The method works if you provide an array. The output of is (the number after @ is almost always different) Please tell us the return type of Employee.getSelectCancel()

What is the meaning of “%d:%02d” in `printf`?

Even though I’m not 100% sure what “%d:%02d” means Here you go: %d means an integer : is a : %02d means an integer, left padded with zeros up to 2 digits. More info at https://docs.oracle.com/javase/8/docs/api/java/util/Formatter.html#syntax

InvalidKeyException Illegal key size

This error means that your Java virtual machine uses a policy that only allows restricted cryptography key sizes due to US export laws. Java 9 and higher The Unlimited Strength Jurisdiction Policy Files are included with Java 9 and used by default (see Security Updates in the Java 9 Migration Guide). If you get this error … Read more

Hata!: SQLSTATE[HY000] [1045] Access denied for user 'divattrend_liink'@'localhost' (using password: YES)