# Reports:Tasks not implemented in Java

**Awareness**

If

**Java**is a language you like, or are interested in, please inform your fellow members of the Java community; this page can't be emptied without your and their participation.

## Contents

## Not implemented[edit]

These are currently not implemented in Java. Please implement some if you can. If any tasks are not possible or too complex in Java, they should not be on this list. To mark a task as such, add **{{omit from|Java}}**, preserving the capitalization of the language, to that task. It will appear below under the "Not Considered" section.

### A

### B

### C

- Calkin-Wilf sequence
- Catmull–Clark subdivision surface
- Check output device is a terminal
- Color quantization
- Colour pinstripe/Printer
- Compare sorting algorithms' performance
- Compiler/virtual machine interpreter
- Composite numbers k with no single digit factors whose factors are all substrings of k
- Conjugate transpose
- Consecutive primes with ascending or descending differences
- Cullen and Woodall numbers
- Curzon numbers
- Cyclops numbers

### D

### E

### F

### L

### M

- Machine code
- Magic constant
- Main step of GOST 28147-89
- Mastermind
- Matrix digital rain
- Mayan calendar
- Median filter
- Merge and aggregate datasets
- Metaprogramming
- Mind boggling card trick
- Minimum multiple of m where digital sum equals m
- Minkowski question-mark function
- Modified random distribution
- Monads/List monad
- Monads/Maybe monad
- Monads/Writer monad
- Motzkin numbers
- Multi-base primes
- Musical scale

### N

### P

- P-Adic numbers, basic
- P-Adic square roots
- Padovan n-step number sequences
- Padovan sequence
- Particle fountain
- Pell numbers
- Percolation/Bond percolation
- Percolation/Mean cluster density
- Percolation/Mean run density
- Percolation/Site percolation
- Periodic table
- Peripheral drift illusion
- Pinstripe/Printer
- Play recorded sounds
- Pragmatic directives
- Pseudo-random numbers/Middle-square method
- Pseudo-random numbers/Splitmix64

### R

### S

- SOAP
- Scope/Function names and labels
- Search in paragraph's text
- Selectively replace multiple instances of a character within a string
- Set right-adjacent bits
- Sierpinski arrowhead curve
- Simple turtle graphics
- Sleeping Beauty problem
- Smallest number k such that k+2^m is composite for all m less than k
- Sort an outline at every level
- Speech synthesis
- Square form factorization
- Strassen's algorithm
- Suffixation of decimal numbers
- Summarize primes
- Sylvester's sequence

### T

- Table creation/Postal addresses
- Tarjan
- Terminal control/Coloured text
- Terminal control/Cursor movement
- Terminal control/Cursor positioning
- Terminal control/Dimensions
- Terminal control/Hiding the cursor
- Terminal control/Inverse video
- Terminal control/Positional read
- Terminal control/Unicode output
- The sieve of Sundaram
- Topic variable
- Tree datastructures
- Tree from nesting levels
- Two's complement
- Two bullet roulette

### Draft tasks without implementation[edit]

These tasks are drafts, meaning they largely need more work to turn them into full tasks. Perhaps you can help by trying to implement them in Java (after all, one of the key requirements for a task being non-draft is multiple implementations, preferably in widely different languages) but be aware that this may be difficult because of lack of definition of the task itself.

### A

### B

### C

- CLI-based maze-game
- Camel case and snake case
- Change e letters to i in words
- Checksumcolor
- Chess player
- Code Golf: Code Golf
- Collect and sort square numbers in ascending order from three lists
- Combinations with repetitions/Square digit chain
- Common list elements
- Common sorted list
- Compiler/Preprocessor
- Compiler/Simple file inclusion pre processor
- Compiler/Verifying syntax
- Concatenate two primes is also prime
- Conjugate a Latin verb
- Continued fraction/Arithmetic/G(matrix ng, continued fraction n)
- Continued fraction/Arithmetic/G(matrix ng, continued fraction n1, continued fraction n2)
- Coprime triplets
- Coprimes
- Count how many vowels and consonants occur in a string
- Count the coins/0-1
- Cousin primes
- Create an executable for a program in an interpreted language
- Create your own text control codes
- Cross compilation
- Cubic special primes
- Curve that touches three points
- Cycles of a permutation

### D

- Dating agency
- Day of the week of Christmas and New Year
- Digit fifth powers
- Diophantine linear system solving
- Discrete Fourier transform
- Distinct palindromes within decimal numbers
- Distinct power numbers
- Distribution of 0 digits in factorial series
- Divide a rectangle into a number of unequal triangles
- Doubly-linked list/Element removal
- Draw pixel 2

### E

### F

- Factorial primes
- Fibonacci heap
- Find URI in text
- Find adjacent primes which differ by a square integer
- Find first missing positive
- Find minimum number of coins that make a given value
- Find prime n such that reversed n is also prime
- Find prime numbers of the form n*n*n+2
- Find square difference
- Find squares n where n+1 is prime
- Find words which contain the most consonants
- Find words which contains all the vowels
- Find words which contains more than 3 e vowels
- Find words whose first and last three letters are equal
- Find words with alternating vowels and consonants
- Four sides of square

### G

### I

### L

- Largest difference between adjacent primes
- Largest five adjacent number
- Largest palindrome product
- Largest prime factor
- Largest product in a grid
- Last list item
- Launch rocket with countdown and acceleration in stdout
- Long stairs
- Longest palindromic substrings
- Longest substrings without repeating characters

### M

### N

- N-queens minimum and knights and bishops
- Names to numbers
- Native shebang
- Neighbour primes
- Number triplets game
- Numbers divisible by their individual digits, but not by the product of their digits.
- Numbers in base-16 representation that cannot be written with decimal digits
- Numbers in base 10 that are palindromic in bases 2, 4, and 16
- Numbers which binary and ternary digit sum are prime
- Numbers whose count of divisors is prime
- Numbers with same digit set in base 10 and base 16

### O

### P

- Palindromic primes
- Palindromic primes in base 16
- Pan base non-primes
- Pandigital prime
- Parse EBNF
- Parse command-line arguments
- Permutations with some identical elements
- Piprimes
- Polynomial derivative
- Positive decimal integers with the digit 1 occurring exactly twice
- Price list behind API
- Prime numbers p for which the sum of primes less than or equal to p is prime
- Prime numbers which contain 123
- Prime triplets
- Prime words
- Primes which contain only one odd digit
- Primes whose first and last number is 3
- Primes with digits in nondecreasing order
- Primorial primes
- Print itself
- Process SMIL directives in XML data

### R

- Range modifications
- Raster bars
- Recursive descent parser generator
- Red black tree sort
- Remote agent/Agent interface
- Remote agent/Agent logic
- Remote agent/Simulation
- Resistance calculator
- Resistance network calculator
- Reverse the order of lines in a text file while preserving the contents of each line
- Rodrigues’ rotation formula
- Rosetta Code/List authors of task descriptions
- Rosetta Code/Run examples
- Round-robin tournament schedule
- Run as a daemon or service

### S

- Safe and Sophie Germain primes
- Safe mode
- Sanitize user input
- Segmentation fault protection
- Self-hosting compiler
- Separate the house number from the street name
- Show the (decimal) value of a number of 1s appended with a 3, then squared
- Simulated annealing
- Sine wave
- Singly-linked list/Element removal
- Smallest enclosing circle problem
- Smallest multiple
- Smallest numbers
- Smallest power of 6 whose decimal expansion contains n
- Smallest square that begins with n
- Solve a Rubik's cube
- Solve equations with substitution method
- Solve hanging lantern problem
- Solving coin problems
- Sort primes from list to a list
- Sort the letters of string in alphabetical order
- Special divisors
- Special factorials
- Special neighbor primes
- Special pythagorean triplet
- Spoof game
- Starting a web browser
- Steady squares
- Substring primes
- Sum of first n cubes
- Sum of primes in odd positions is prime
- Sum of square and cube digits of an integer are primes
- Sum of the digits of n is substring of n
- Sum of two adjacent numbers are primes
- Summation of primes
- Sunflower fractal

### T

- Table creation
- Tamagotchi emulator
- Terminal control/Restricted width positional input/No wrapping
- Terminal control/Restricted width positional input/With wrapping
- Text to HTML
- Three word location
- Time-based one-time password algorithm
- Transliterate English text using the Greek alphabet
- Triplet of three numbers
- Tropical algebra overloading

### U

### W

## Requiring Attention[edit]

### Examples[edit]

These tasks have implementations in Java, but somebody, somewhere, decided that the example implementation was faulty or in some other way requiring attention. If you're familiar with the task and language, please consider reviewing/correcting the example and removing the notice.

### F

### M

### R

### U

### Y

### Other pages[edit]

These are other pages related to Java which require attention; with your knowledge and assistance, we can improve the quality of the site's content.

### No pages found.

## Not Considered[edit]

These tasks are not generally counted toward "unimplemented", as somebody, somewhere, decided that Java was inappropriate for these tasks, or implementations of them would be unenlightening. Feel free to try your hand at them anyway.

### C

### P

## End of List[edit]

Again, feel free to try your hand at any of the tasks listed on this page.