JetBrains has released IntelliJ IDEA 2021.1 which is specially support for Java 16. New release instantly renders HTML changes, and support for WSL 2 and support to run applications on Docker, WSL 2 or via SSH.

IntelliJ is supporting to declare static members within inner classes which is featured at Java 16.

class InnerClass { 
    static final String STATIC_VALUE = new String("Hello World");
    static String display() {       
        return STATIC_VALUE;
    }
}

Warnings displays whenever an array or a condition has a negative size. Another warning is displayed when the Collection.toArray() method misused times.