Easily read text files in Java (Java 11 & Java 7)

Overview

--Use Files.readString and Path.of in Java 11 environment --Use Files.readAllLines, Files.readAllBytes and Paths.get in Java 7 environment

Sample code Cat.java

import java.io.IOException;
import java.nio.charset.Charset;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.util.List;

public class Cat {

    public static void main(String[] args) throws IOException {
        String path = args[0];
        System.out.print(readString11(path));
        System.out.print(readString7(path));
        // String.join is Java 8 or later
        System.out.println(String.join(System.lineSeparator(), readLines7(path)));
    }

    /**
     *Read a text file. Methods available from Java 11.
     * @param path path of the file to read
     * @contents of return file
     * @throws IOException
     * @throws OutOfMemoryError
     * @throws RuntimeException
     */
    public static String readString11(String path) throws IOException {
        return Files.readString(Path.of(path), Charset.forName("UTF-8"));
    }

    /**
     *Read a text file. Methods available from Java 7.
     * @param path path of the file to read
     * @contents of return file
     * @throws IOException
     * @throws RuntimeException
     */
    public static String readString7(String path) throws IOException {
        return new String(Files.readAllBytes(Paths.get(path)), Charset.forName("UTF-8"));
    }

    /**
     *Read a text file. Methods available from Java 7.
     * @param path path of the file to read
     * @contents of return file
     * @throws IOException
     * @throws RuntimeException
     */
    public static List<String> readLines7(String path) throws IOException {
        return Files.readAllLines(Paths.get(path), Charset.forName("UTF-8"));
    }
}

Sample execution result

compile.

$ javac Cat.java

Prepare a text file.

$ cat sample.txt 
sample
sample
SANNPURU

Run the sample code.

$ java Cat sample.txt 
sample
sample
SANNPURU
sample
sample
SANNPURU
sample
sample
SANNPURU

Operation check environment

$ java -version
java version "11.0.1" 2018-10-16 LTS
Java(TM) SE Runtime Environment 18.9 (build 11.0.1+13-LTS)
Java HotSpot(TM) 64-Bit Server VM 18.9 (build 11.0.1+13-LTS, mixed mode)

$ uname -mrsv
Darwin 18.2.0 Darwin Kernel Version 18.2.0: Fri Oct  5 19:41:49 PDT 2018; root:xnu-4903.221.2~2/RELEASE_X86_64 x86_64

$ sw_vers
ProductName:    Mac OS X
ProductVersion: 10.14.1
BuildVersion:   18B75

Reference material

--English reference

--Japanese reference