JAVA PROGRAM • LEVEL 07 — STRINGS & TEXT PROCESSING
Reverse a String in Java
Learn reverse a string in java with a complete, compiler-ready Java 17 example.
PROBLEM UNDERSTANDING
Input and expected output
No input required
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COMPLETE JAVA 17 PROGRAM
Complete Java 17 implementation
class Main {
public static void main(String[] args) throws Exception {
String text="Java";
System.out.println(new StringBuilder(text).reverse());
}
}CURRENT STEP
Select Start to walk through the important lines.
SELECTED LINE
No line selected
EXPECTED OUTPUT FOR THE SAMPLE
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PROGRAM EXPLANATION
Algorithm and explanation
- Initialize the deterministic sample values used for reverse a string in java.
- Create the required object and apply StringBuilder and reverse() to its state or behavior.
- Print the final result and compare it with the documented sample output.
This Java 17 example demonstrates StringBuilder and reverse() through a complete, executable program. The values are intentionally small so students can trace each statement, verify the output, and then modify the example safely in the online compiler.
EFFICIENCY
Time and space complexity
O(n)
O(1)
DEBUGGING CHECKLIST
Common mistakes
Keep the class name Main and the entry method signature public static void main(String[] args) when using the online compiler.
Use StringBuilder with compatible Java types; Java checks types and method signatures at compile time.
Java is case-sensitive, and every statement that requires a semicolon must end with one.