Tag: io

is checking if a file object exists redudent and bad style when you have a try, catch block?

Is it overly redundant and considered bad style to check that the file object exists before a try catch. Since the FileNotFoundException would be called anyways if the file object did not exist? Answer Yes, the exists test is redundant. An implicit existence test happens within the Scanner. (Actually, it occu…

How to use SequenceInputStream?

io java

🍳Background 1.I was learning the basic grammar of input and output in java. 2.But I found that the SequenceInputStream worked strangely. ⚡Code ⚡outcome 🔑Question 1.Why did the method(read) stop when meet EOF? 2.How to read the next Stream? Answer Why did the method(read) stop when meet EOF? You might be expec…

How can I remove last 2 lines in text file in Java?

io java

I want remove last 2 lines in my text file using java. I tried 4 or 5 different ways about this, but I can’t find working code. I will edit file like this: I want delete “]” , “}” and add “example2”. How can I do that ? (I’m using SE 1.8 , maybe version have an …

How to get rid of – “java.io.IOException: The system cannot find the path specified”

file io java

I am trying to create a file and write to it, but I’m getting error in my path. Here is my code: Answer You can’t have a folder and a file with the same name in the same path location. That’s why this code fails: Here you’re first creating a folder, and then you’re attempting to create a file with…

Does commons-io’s FileUtils.readFileToByteArray close the newly created stream?

apache-commons-io io java

I’m creating a program that produce checksums for each files in directory. I’m using FileUtils.readFileToByteArray which internally creates a new FileInputStream. The problem is I didn’t find where the stream is closed and wondering about a possible memory leak. So I’m asking: does thi…

How to save the matrix in the text file

arrays file input io java

I just want to input the matrix in the text file, but the result are clearly different. I don’t have any ideas. I expect but in the file is Answer You can try this: This will print the values like a table:

How to perform unbuffered input in Java (if at all possible)?

buffer io java

Java Beginner here. When we input a string, we have to press the enter key to let the program know that the user has done inputting. Is there a way where we use another key instead of enter key (for example a question mark key) to input a string? Answer Ever heard of something called a “buffer”? I…

get removable sd card path in android

android io java storage

How can i get extSdcard path in android? There are 2 storage, first external storage in which all the phones have it but there is second storage which is called removable storage (micro sdcard). I want to get the path to the micro sdcard in android, how is that possible? Answer Starting from KitKat, you have …

Ignoring blank lines in CSV file in Java

bufferedreader csv io iteration java

I am trying to iterate through a CSV file in Java. It iterates through the entire file, but will get to the end of the file and try to read the next blank line and throw an error. My code is below. Like I typed, this works fine until it gets to the end of the file. When it gets

Code in “catch” block not executing

catch-block exception io java

please help me understand why:) My program reach the “try” line, but seems to skip the “catch”, Although its printing the stacktrace… I’m using JOptionPane in my catch, but also System.out.println() not working. Code: Exception: Answer There is an NullPointerException inter…