Creating New Directories in Java
Learn to create a new single directory or nested directory along with parent directories in a specified path using Java IO and NIO classes.
Count Number of Lines in a File in Java
Learn to count all the lines in file with the efficient solutions like Stream of lines, List and LineNumberReader classes.
How to Check if a Directory is Empty in Java
Learn to a few performance-proven methods to check if a given directory is empty or not using the Java NIO Files and DirectoryStream classes.
Getting File Creation Timestamp in Java
Learn to get the creation date and time of a file in Java using Java NIO Files class in different time units since epoch and to Instant.
Working with Symbolic Links with Java
Learn to create, detect and find targets of the symbolic links (also known as symlinks or soft links) using examples in Java.
How to Delete the Contents of a File
Learn to make the file empty by deleting all the content in it. This makes the file size zero without deleting the file itself.
Writing Byte[] to a File in Java
Learn to write the given byte[] into a file using different solutions. We will be using the Java NIO, Commons IO and Guava APIs that provide simple APIs for this usecase.
Reading a File into ArrayList in Java
Learn to read all the lines from a file into ArrayList using Java IO and NIO APIs, Stream API, Commons IO and Guava classes.
Reading a File at a Given Line Number in Java
Learn to read a specific line from a text file in Java. We will learn to write the solution for small files as well as large files as well.
Reading a Large File Efficiently in Java
Learn to read all lines from a large file (size in GB) in Java and avoid any performance pitfalls such as very high usage of memory or even OutOfMemoryError if the File is large enough.
Deleting a File or Directory in Java
Learn to delete a specified file or directory in Java. Note that different methods behave differently for deleting non-empty directories.
Rename or Move a File or Directory in Java
Learn to rename a file or directory at a specified path or move to a new directory in Java. We will learn to use the classes from Standard IO, New IO, Guava and Commons IO.
Getting Filesystem Paths in Java
Learn the difference between path, absolute and canonical paths. Also, learn to get the path of a file in Java using standard IO and New IO classes.
Java Get File Size (with Examples)
Learn to get the size of a file or a directory in Java using IO classes File, Files and Common IO’s FileUtils class.
JUnit 5 @TempDir Example: Temp Directory / File Support
Sometimes tests require temporary directories and files for performing intermediate test steps. JUnit 5 provides the @TempDir annotation that supplies a temporary directory to the test method or lifecycle methods. 1. JUnit @TempDir Annotation JUnit Jupiter provides an extension model that allows us to extend the behavior of the test …
Java FileWriter
The Java FileWriter class is for writing the text to the character-based files using a default buffer size. It uses character encoding default to the platform, if not provided otherwise. FileWriter is usually wrapped by higher-level Writer types, such as BufferedWriter or PrintWriter. FileWriter provides better performance and higher-level, more …
Java FileReader
Java FileReader class can be used to read data (stream of characters) from files. In this tutorial, we will learn about FileReader class, its constructors, methods and usages with the help of examples. 1. Introduction The FileReader class is: 2. Creating FileReader To use the FileReader in the application, we …
Reading a File from Classpath in Java
Learn to read a file from classpath in Java. The file can be present at root of class path location or in any relative sub-directory.
String lines() – Get stream of lines – Java 11
Learn to convert multi-line string into stream of lines using String.lines() method in Java 11. This method is useful when we want to read content from a file and process each string separately.
Java 11 Files.writeString(): Writing Text to a File
Learn to write a string into file in Java using Files.writeString(path, string, options) method. This API has been introduced in Java 11.
Java 11 Files.readString()
Learn to read a file to string in Java using Files.readString(path) method. This API has been introduced in Java 11.
Appending to a File in Java
Learn to append the data to a file in Java using Standard IO’s BufferedWritter, PrintWriter, FileOutputStream and NIO Files classes.
Java Write to File: Clean Code vs. Performance
Learn to write text and binary data into files using Java Writer, FileChannel, ByteBuffer, Files.write() and writeString() methods in Java 8 and Java 11.
Java Read File to String (with Examples)
Learn to read a text file into String using Files.readAllBytes(), Files.lines() and BufferedReader classes in various ways.
Java Unzip File with Sub-directories
Java examples of unzipping and extracting the zip file using java.util.zip package and apache commons compress module.
Read a File from Resources Directory
Java examples of reading a file from the resources folder from a jar file, war file, spring application or the development environment.
Copying a Directory in Java
Learn to copy a directory into a new location in Java. Learn to apply FileFilter to include or exclude subdirectories and specific files.
Making a File Read-Only in Java
Learn to make a file read-only in Java. A read-only file can be opened for reading, but we cannot modify or delete the file contents.
Copying a File in Java
Copying a file from one place to another in Java is a common task. Learn to copy files using Java NIO, Commons-IO and Guava APIs.
Java FilenameFilter to Find Files Matching Pattern
Learn to use the Java FilenameFilter to traverse a directory and search all files with names matching a specified pattern.
Creating a New File in Java
Learn to create a new file using different techniques including NIO Files and Path, IO File, File OutputStream, and open-source libraries.
Java NIO FileChannel transferTo() and transferFrom()
When using FileChannel transferTo() and transferFrom() methods, data doesn’t pass through the Java heap, thus reducing garbage collection pressure.
Java Delete Temporary File
Learn how to delete a temporary file in Java. We will see examples to use File.deleteOnExit() and File.delete() methods.
Java Create Temp File or Directory
Learn to create a temp file and directory in Java using the legacy and NIO classes. Also, learn to delete temp files or temp directories on JVM shutdown.
Writing to Temporary File in Java
Learn to create a temporary file and write to it in Java. We will use the code sample used for creating a temporary file example.
Check If a File or Directory Exists in Java
Learn to check if a file exists or a directory exists in given path in Java. Also check is file is readable, writable or executable.
Read File to Byte[] in Java
Learn reading data from files into a byte array in Java using NIO Files, FileInputStream, Commons IO FileUtils, and Guava ByteStreams classes.
Reading and Writing UTF-8 Data into File
Learn reading and writing UTF-8 content into a file using BufferedReader and BufferedWriter in Java.
Guide to Java LineNumberReader
For reading a file line by line, the LineNumberReader class could be used that allows to keep track of which line we are currently processing.
Java Read and Write Properties File Example
Learn to read property file in java using Properties.load() method. Then we will use Properties.setProperty() method to write a new property into file,
Java FileFilter (with Examples)
Java FileFilter accepts File objects and thus can be used to filter the files based on other attributes such as read-only, directory etc.
Delete a Directory Recursively in Java
Learn to use classes from Java IO, New IO and Commons IO to delete a directory including all the subdirectories and files in it.
Java Read a File Line by Line
In this Java tutorial, we will learn to read a text file line-by-line methods such as Streams or FileReader. We will also learn to iterate through lines and filter the file content based on some conditions. 1. Files.lines() – Stream through Lines of a File in Java 8 The Files.lines() …
Parse and Read a CSV File in Java
In Java, there are different ways of reading and parsing CSV files. Let’s discuss some of the best approaches such as OpenCSV, Super CSV etc.
Reading a File with Channels and Buffers
Learn to read small and large files from the filesystem using the Java NIO APIs Path, FileChannel, ByteBuffer and MappedByteBuffer.