Package com.github.javaparser.ast.expr

Class InstanceOfExpr

java.lang.Object
com.github.javaparser.ast.Node
com.github.javaparser.ast.expr.Expression
com.github.javaparser.ast.expr.InstanceOfExpr
All Implemented Interfaces:
NodeWithExpression<InstanceOfExpr>, NodeWithRange<Node>, NodeWithTokenRange<Node>, NodeWithType<InstanceOfExpr,​ReferenceType>, Observable, Visitable, HasParentNode<Node>, Cloneable
public class InstanceOfExpr extends Expression implements NodeWithType<InstanceOfExpr,​ReferenceType>, NodeWithExpression<InstanceOfExpr>

The instanceof statement

Java ?? to 13

The instanceof expression is a relational operator, evaluating to true if the object on the left hand side is an instance of the type (ReferenceType) on the right hand side.

Example:
tool instanceof Drill

This is then used wherever a conditional/boolean value can be used. For example: 
if (obj instanceof String) {
     String s = (String) obj;
     // use s
 }

Java 14

Since JDK14, it is possible to bind a variable that is cast to the type being tested against. This is referred to as a Pattern within JEP305, and avoids the need to cast to the desired type.
Example:
tool instanceof Drill d

This is then used wherever a conditional/boolean value can be used. The scope of the variable created can vary, and is defined further within JEP305. 
if (obj instanceof String s) {
     // can use s here
 } else {
     // can't use s here
 }


JDK14 Grammar

Per JEP305: 
RelationalExpression:
      ...
      RelationalExpression instanceof ReferenceType
      RelationalExpression instanceof Pattern

 Pattern:
      ReferenceType Identifier
Author:
Julio Vilmar Gesser
See Also:
PatternExpr, JEP305: https://bugs.openjdk.java.net/browse/JDK-8181287, https://docs.oracle.com/javase/specs/jls/se11/html/jls-15.html#jls-15.20