can anyone explain this?

a while ago.. i was coding a program , editing it, compiling it. and suddenly the electricity went out..
then it came back.. and then I continued coding the program again and the electricity went out again..

after a few hours.. I saw one of the .java files in my package indicating that there was an error..
i checked it out.. but theres nothing wrong.. so what I did is I copied that .java file(I didnt change anything) and then pasted it in another blank file.. then the error disappeared..(it compiled normlaly)

and the program's code that I was editing was corrupted and became a series of square characters..
(a character that will be made by pressing 'ctrl + backspace' )

what happened to my IDE?
will I have any future problem regarding this matter?
coz i have lots of exercises in my files.. and if woud i have any future errors..OH GOD.. im gonna edit it all.
I was bothered by that problem that the last program's code that i was editing became a series of
square characters.(ctrl + backspace)

Are you using Eclipse? Yeah, I have that problem too sometimes. It's nothing serious, it happens because of the way Eclipse tracks errors/builds. If you do a clean build, it should get rid of all the errors.

Yeah, you can select Project -> Clean in the menu and clean that specific project and it will remove all errors on it.

// Json

Hold up!Hold up!Hold up ya'll!

What is this Eclipse? Is it a Java compiler?

Help!!

Eclipse is a full blown IDE for developing in C++, Java, PHP or whatever language you fancy really. Have a look at Eclipse.org home

// Json