Enum : valueOf

public static <T extends Enum<T>> T valueOf(Class<T> enumType, String name)

Returns the enum constant of the specified enum type with the specified name.

enum Day{
 MON,
 TUE,
 WED,
 THU,
 FRI,
 SAT,
 SUN;
 
 public static void main(String args[]){
  Class<Day> enumType = Day.class;
  
  Enum<Day> dayVal = Enum.valueOf(enumType, "MON");
  System.out.println(dayVal.name());
  
  dayVal = Enum.valueOf(enumType, "TUE");
  System.out.println(dayVal.name());
  
  dayVal = Enum.valueOf(enumType, "WED");
  System.out.println(dayVal.name());
  
  dayVal = Enum.valueOf(enumType, "THU");
  System.out.println(dayVal.name());
  
  dayVal = Enum.valueOf(enumType, "FRI");
  System.out.println(dayVal.name());
  
  dayVal = Enum.valueOf(enumType, "SAT");
  System.out.println(dayVal.name());
  
  dayVal = Enum.valueOf(enumType, "SUN");
  System.out.println(dayVal.name());
 }
}

Output

MON
TUE
WED
THU
FRI
SAT
SUN

1. throws IllegalArgumentException if the specified enum type has

no constant with the specified name, or the specified class object does not represent an enum type

enum Day{
 MON,
 TUE,
 WED,
 THU,
 FRI,
 SAT,
 SUN;
 
 public static void main(String args[]){
  Class<Day> enumType = Day.class;
  
  Enum<Day> dayVal = Enum.valueOf(enumType, "ABC");
  System.out.println(dayVal.name()); 
 }
}

Output

Exception in thread "main" java.lang.IllegalArgumentException: No enum constat
Day.ABC
        at java.lang.Enum.valueOf(Enum.java:236)
        at Day.main(Day.java:13)

2. throws NullPointerException if enumType or name is null

enum Day{
 MON,
 TUE,
 WED,
 THU,
 FRI,
 SAT,
 SUN;
 
 public static void main(String args[]){
  Class<Day> enumType = Day.class;
  
  Enum<Day> dayVal = Enum.valueOf(enumType, null);
  System.out.println(dayVal.name()); 
 }
}

Output

Exception in thread "main" java.lang.NullPointerException: Name is null
        at java.lang.Enum.valueOf(Enum.java:235)
        at Day.main(Day.java:13)

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