Character.isJavaIdentifierPart() Method in Java with Examples

1. The Character.isJavaIdentifierPart(int codePoint) is an inbuilt method in java that determines if the specified character may be part of a Java identifier as other than the first character.
   A character may be a part of Java identifier if any of the following are true:
   • it is a letter
   • it is a currency symbol (such as ‘$’)
   • it is a connecting punctuation character (such as ‘_’)
   • it is a digit
   • it is a numeric letter (such as a Roman numeral character)
   • it is a combining mark
   • it is a non-spacing mark
   • isIdentifierIgnorable returns true for the character.

   Syntax:

   public static boolean isJavaIdentifierPart(int codePoint)

   Parameters: The parameter codePoint of Integer datatype refers to the character (Unicode code point) that is to be tested.

   Return Value: The isJavaIdentifierPart(int codepoint) method of Character class returns true if the character may be part of a Java identifier; false otherwise.

   Below programs are used to illustrate the Character.isJavaIdentifierPart(int codepoint) method:
   Program 1:

   
   

   
   
   

   // Java program to illustrate // Character.isJavaIdentifierPart() method import java.lang.*;    public class gfg {        public static void main(String[] args)     {            // Create 2 int primitives c1, c2         int c1 = 0x01f2, c2 = 0x78c0;            // Assign isJavaIdentifierPart results of c1, c2         // to boolean primitives bool1, bool2         boolean bool1 = Character.isJavaIdentifierPart(c1);         boolean bool2 = Character.isJavaIdentifierPart(c2);            String str1 = "c1 may be part of a Java identifier is " + bool1;         String str2 = "c2 may be part of a Java identifier is " + bool2;            System.out.println(str1);         System.out.println(str2);     } }
   Output:

   c1 may be part of a Java identifier is true
   c2 may be part of a Java identifier is true
   

   Program 2:

   
   

   
   
   

   // Java program to illustrate // Character.isJavaIdentifierPart(int codepoint) method import java.lang.*;    public class gfg {        public static void main(String[] args)     {            // Create 2 int primitives c1, c2         int c1 = 0x85f1, c2 = 0x95c0;            // Assign isJavaIdentifierPart results of c1, c2         // to boolean primitives bool1, bool2         boolean bool1 = Character.isJavaIdentifierPart(c1);         boolean bool2 = Character.isJavaIdentifierPart(c2);            String str1 = "c1 may be part of a Java identifier is " + bool1;         String str2 = "c2 may be part of a Java identifier is " + bool2;            // Print b1, b2 values         System.out.println(str1);         System.out.println(str2);     } }
   Output:

   c1 may be part of a Java identifier is true
   c2 may be part of a Java identifier is true
   

2. The Character.isJavaIdentifierPart(char ch) is similar to the previous method in all manner but cannot handle supplementary characters. To support all Unicode characters, including supplementary characters, use the previous method.

   Syntax:

   public static boolean isJavaIdentifierPart(char ch)

   Parameters:The parameter ch is of character datatype and refers to the character that is to be tested.

   Return Value: The isJavaIdentifierPart(char ch) method of Character class returns true if the character may be part of a Java identifier; false otherwise.

   Below programs are used to illustrate the use Character.isJavaIdentifierPart(char ch) method:
   Program 1:

   
   

   
   
   

   // Java program to illustrate // Character.isJavaIdentifierPart(char ch) method import java.lang.*;    public class gfg {        public static void main(String[] args)     {            // Create 2 char primitives c1, c2 and assign values         char c1 = '5', c2 = '%';            // Assign isJavaIdentifierPart results of          //c1, c2 to boolean primitives bool1, bool2         boolean bool1 = Character.isJavaIdentifierPart(c1);         boolean bool2 = Character.isJavaIdentifierPart(c2);            String str1 = c1 + " may be part of a Java identifier is " + bool1;         String str2 = c2 + " may be part of a Java identifier is " + bool2;            // Print bool1, bool2 values         System.out.println(str1);         System.out.println(str2);     } }
   Output:

   5 may be part of a Java identifier is true
   % may be part of a Java identifier is false
   

   Program 2:

   
   

   
   
   

   // Java program to illustrate // Character.isJavaIdentifierPart(char ch) method import java.lang.*;    public class gfg {        public static void main(String[] args)     {            // Create 2 char primitives c1, c2 and assign values         char c1 = '6', c2 = '*';            // assign isJavaIdentifierPart results of          //c1, c2 to boolean primitives bool1, bool2         boolean bool1 = Character.isJavaIdentifierPart(c1);         boolean bool2 = Character.isJavaIdentifierPart(c2);            String str1 = c1 + " may be part of a Java identifier is " + bool1;         String str2 = c2 + " may be part of a Java identifier is " + bool2;            // Print bool1, bool2 values         System.out.println(str1);         System.out.println(str2);     } }
   Output:

   6 may be part of a Java identifier is true
   * may be part of a Java identifier is false
   

Reference: https://docs.oracle.com/javase/7/docs/api/java/lang/Character.html#isUnicodeIdentifierPart(int)