If you are dealing with a single character value, you can store it in char variable. A single character value is a character inside two quotes. Here is an example:
char mykey = 'a';
A char variable can accept ASCII and UNICODE character. The example above was the ascii character which their numeric value is a number between 0 two 255.
Save following content in a .java file called TryChar.java. Note that the file name is equivalent to your class name TryChar.
public class TryChar {
  public static void main(String[] args) {
     char tryChar1 = 'A';
     System.out.print("tryChar1 char value: ");
     System.out.println(tryChar1);
     System.out.print("tryChar1 ascii code: ");
     System.out.println((int) tryChar1);
     char tryChar2 = 'ß';
     System.out.print("tryChar2 value: ");
     System.out.println(tryChar2);
     System.out.print("tryChar2 ascii code: ");
     System.out.println((int) tryChar2);
     char tryChar3 = 124;
     System.out.print("tryChar3 value: ");
     System.out.println(tryChar3);
     System.out.print("tryChar3 ascii code: ");
     System.out.println((int) tryChar3);
     char tryChar4 = '\u2142';
     System.out.print("tryChar4 value: ");
     System.out.println(tryChar4);
     System.out.print("tryChar4 Unicode code: ");
     System.out.println((int) tryChar4);
  }
}
Using javac command compile your .java file
$ javac TryChar.java
And using java command run it.
$ java TryChar tryChar1 char value: A tryChar1 ascii code: 65 tryChar2 value: ß tryChar2 ascii code: 223 tryChar3 value: | tryChar3 ascii code: 124 tryChar4 value: ⅂ tryChar4 Unicode code: 8514
In Java, a char variable is technically a two bytes (16 bits) variable type that you can assign a single unicode character via the character symbol inside two quotes like this:
char tryChar2 = 'ß';
or assign a number value like this that represent pipe | character:
char tryChar3 = 124;
or you can assign a unicode character:
char tryChar4 = '\u2142';
That represents this character symbol ⅂ with a decimal value of 8514