Implement a String in JShell in Java 9

JShell is Java’s first official REPL application introduced in Java 9. It is a tool that helps in executing and evaluating simple java programs, and small logics such as statements, simple programs, loops, expressions, etc. Java REPL can provide a simple programming environment in a command-line prompt. It reads the input, evaluates it, and prints the output.

In the below example, we can implement a string with pre-defined methods of String class.

Example

jshell> String str = "{abcd}";
str ==> "{abcd}"

jshell> str.substring(2, str.length() - 1)
$7 ==> "bcd"

jshell> String s1 = new String("abcd");
s1 ==> "abcd"

jshell> String s2 = new String("abcd");
s2 ==> "abcd"

jshell> s1 == s2
$10 ==> false

jshell> s1.equals(s2)
$11 ==> true

jshell> String s3 = "abcd";
s3 ==> "abcd"

jshell> String s4 = "abcd";
s4 ==> "abcd"

jshell> s3 == s4
$14 ==> true

jshell> s3.equals(s4)
$15 ==> true

jshell> s1 == s3
$16 ==> false

jshell> s1.equals(s3)
$17 ==> true

jshell> String s5 = "a" + "bcd";
s5 ==> "abcd"

jshell> s3 == s5
$19 ==> true

jshell> "abcd".getBytes()
$20 ==> byte[4] { 97, 98, 99, 100 }

jshell> "abcd".getBytes("UTF-16")
$22 ==> byte[10] { -2, -1, 0, 97, 0, 98, 0, 99, 0, 100 }

jshell> String raw = "1|2|3|4";
raw ==> "1|2|3|4"

jshell> raw.split("\|")
$24 ==> String[4] { "1", "2", "3", "4" }