Java Practice

Every lesson runs in your browser — write real code, press Run, and the tasks check themselves. Free, no account needed, with notes in English and Chinese.

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Lessons in this course

1. 01 Print a word
2. 02 Print another word
3. 03 Print a sentence
4. 04 Print with a !
5. 05 Print two lines
6. 06 Print a number
7. 07 Add two numbers
8. 08 Subtract
9. 09 Multiply
10. 10 Divide
11. 11 Remainder
12. 12 A number variable
13. 13 A text variable
14. 14 Add two variables
15. 15 Your first method
16. 16 Is it positive?
17. 17 Cube a number
18. 18 The smaller one
19. 19 Square a number
20. 20 Largest of three
21. 21 Count the vowels
22. 22 Reverse the word order
23. 23 Palindrome check
24. 24 Running sum
25. 25 Most frequent character
26. 26 Binary search
27. 27 Factorial (mind the size)
28. 28 Count primes below n
29. 29 Roman numerals
30. 30 Longest common prefix

Language reference

/know/reference/java