Can't resolve method readAllBytes()

Question

What I’m trying to do

I'm trying to build a java.net application where client and server have to send data to each other via serialised collection types as byte[].

The problem

For an unknown reason my DataInputStream can't resolve the method readAllBytes().

A friend threw it in his IDE and it didn't complain. I'm unsure how this could be a version issue, but I checked and I didn't misconfigure my project. I'm using Java 8.

  public void startClient() {
        try {
            Socket client = new Socket("localhost", 7000);
            DataOutputStream out = new DataOutputStream(client.getOutputStream());
            out.writeUTF("Hi i'm " + client.getLocalSocketAddress());
            DataInputStream input = new DataInputStream(client.getInputStream());
            byte[] sent = input.readAllBytes(); //"can't resolve method 'readAllBytes()'
            getDataFromClient(input.readAllByes());//"can't resolve method 'readAllBytes()'
            client.close();


        } catch (UnknownHostException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

I'm actually sure this method should be supported, but I can't figure out why it isn't since it is listed as a method, inherited from Input Stream (docs.oracle.com).

The project, containing the method is also a Gradle Project. Hence, to complete the picture, this is the build.gradle:

plugins {
    id 'java'
    id 'application'
}

sourceSets {
    main {
        resources {
            srcDirs = ["src/main/java"]
            includes = ["**/*.fxml","**/*.png"]
        }
    }
}

group 'prog3'
version '0.1'
mainClassName='Client'

sourceCompatibility = 1.8
targetCompatibility = 1.8

repositories {
    mavenCentral()
}

dependencies {
    testImplementation 'org.junit.jupiter:junit-jupiter-api:5.3.1'
    testCompile group: 'org.mockito', name: 'mockito-core', version: '2.1.0'
}

Edit: Turns out as per the answers, Java 8 was insufficient and I should have used Java 9. Classic RTFM question.

Answer 1

As per InputStream.readAllBytes() method javadoc this method was introduced in Java 9.

Since:

9

It won't work when the code is compiled on lower Java version, in your case Java 8.