java programming - need help, urgent!

i need some serious help with this java project that i have to deliver tomorrow... i don't know much about java so any help is good.

the program goes like this:

- Code a little application for creation and visualization of small files, and also a little calculator to make simple operations (addition,
subtraction, multiplication, division and square root).
- While executed, the application must ask the user if he wants to use the text processor, the calculator or exit the program.
- Chosing the text processor, the user may chose between creating a new text file or read an existing one.
- If the user choses to read a file, he must write the name of the file, andhaveaccess to the content of the file.
- If the user choses to create a file, he must insert the text till he writes #END# in an isolated line, after that he must chose the name of
the file where to save the text.
- In the end of any of the options, the user should return to the main question: use to text processor, calculator or exit.

Observations:
- When you "implement" the application, you must use a class to the text processor, another to the calculator, and another to combine both
and the interaction with the user, and any other you think its necessary.
Optional:
- Write a little report that includes the geral scheme of the application (relating the classes and methods and how
these are linked)


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this is how it should look:

WELCOME TO WORLDCAC!

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- Which option you want to execute? Text Processor [WORD], Calculator [CALC], or Exit [EXIT]?
WORD

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- Would you like to read a file [READ] or create a new one [WRITE]?
READ

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- What's the name of the file?
read_text.rxt
- The content of the file is:
The happy dogs make me happy.
The happy dogs make me happy.

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- Which option you want to execute? Text Processor [WORD], Calculator [CALC], or Exit [EXIT]?
WORD

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- Would you like to read a file [READ] or create a new one [WRITE]?
WRITE
- Insert the content of the file (end with #WNS# in an isolated line)
The happy dogs love jah.
The happy dogs love jah.
- What's the name of the file?
one.txt
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- Which option you want to execute? Text Processor [WORD], Calculator [CALC], or Exit [EXIT]?
CALC

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- Which operation you want to execute: addition [ADD], subtraction [SUB], multiplication [MULT], division
[DIV] or square root [ROOT]?
ROOT
- What's the value you want to use?
25
- The result is 5.0.

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- Which option you want to execute? Text Processor [WORD], Calculator [CALC], or Exit [EXIT]?
EXIT



{the end}

NOTE: The italic text represents the data inserted by the user. (on other words, it represents what the user has writen!)


thanks for the help.
muchas gracias.
obrigado.