Apex Reserved keyword
1. Class
This keyword is used to define a class.
Example
private class MyClass {
private Integer number;
public Integer getNumber() {
return number;
}
}
2. Abstract
This keyword is used to define abstract classes. An abstract class that contains methods only have a signature and no body is defined. Can also define methods.
Example
public abstract class MyAbstrtactClass {
protected void myMethod1() {
/* instruction */
}
abstract Integer myAbstractMethod1();
}
3. Implements
This keyword is used to declare a class that impediments an interface.
Example
global class CreateTaskEmailExample implements Messaging.InboundEmailHandler {
global Messaging.InboundEmailResulthandleInboundEmail(Messaging.inboundEmail email,Messaging.InboundEnvelope env) {
// do some work, return value;
}
}
4. extends
Defines a class that extends another class.
Example
public class MyClass1 extends MyClass {
// code
}
5. interface
This keyword is used to define a data type with method signatures. Classes implement interfaces. An interface can extend another interface.
Example
public interface PO {
public void doWork();
}
public class MyPO implements PO {
public override doWork() {
// actual implementation
}
}
6. virtual
This keyword Defines a class or method that allows extension and overrides. You can’t override a method with the override keyword unless the class or method has been defined as virtual.
Example
public virtual class MyException extends Exception {
// Exception class member
// variable
public Double d;
// Exception class constructor
MyException(Double d) {
this.d = d;
}
// Exception class method
protected void doIt() {
}
}