Thread: Tutorials code not working with variables and arrays

Hi everyone. I am new to Java but not new to programming, yet I can't get through any tutorials because the code keeps failing.

The first thing I noticed is I need to write: // This line

public static void main(String[] args) {
Main here = new Main(); // This line
System.out.println(here.testString);
}

In order to output variables because they are non-static? Tutorials don't get into that.

Also, why can't I change the contents of an array with:

testArray[1] = "black";

Examples claim I can do this but Java 17.0.1 will not allow it.

package com.mycompany.helloworld;
 
public class Main {
 
    String testString = "Welcome to the Matrix";
    int theLength = testString.length();
 
    String colors = "red, green, blue, grey, yellow, black";
    String[] splitColors = colors.split(", ");
 
    int[] testArray = {21, 32, 43, 54, 65, 76};
    String[] testArray2 = {"red", "blue", "yellow"};
    testArray2[1] = "black";
 
    public static void main(String[] args) {
        Main mod = new Main();
        System.out.println(mod.testString);
        System.out.println(mod.theLength);
        System.out.println(mod.splitColors[0]);
        System.out.println(mod.testArray[1]);
        System.out.println(mod.testArray.length);
        System.out.println(mod.testArray2[1]);
 
    }
 
}

--- Update ---

cd C:\Users\pstad\Documents\NetBeansProjects\HelloWor ld; "JAVA_HOME=C:\\Program Files\\Microsoft\\jdk-17.0.1.12-hotspot" cmd /c "\"C:\\Program Files\\NetBeans-12.6\\netbeans\\java\\maven\\bin\\mvn.cmd\" -Dexec.vmArgs= \"-Dexec.args=${exec.vmArgs} -classpath %classpath ${exec.mainClass} ${exec.appArgs}\" -Dexec.appArgs= -Dexec.mainClass=com.mycompany.helloworld.Main \"-Dexec.executable=C:\\Program Files\\Microsoft\\jdk-17.0.1.12-hotspot\\bin\\java.exe\" \"-Dmaven.ext.class.path=C:\\Program Files\\NetBeans-12.6\\netbeans\\java\\maven-nblib\\netbeans-eventspy.jar\" -Dfile.encoding=UTF-8 org.codehaus.mojo:exec-maven-plugin:3.0.0:exec"
Running NetBeans Compile On Save execution. Phase execution is skipped and output directories of dependency projects (with Compile on Save turned on) will be used instead of their jar artifacts.
Scanning for projects...

----------------------< com.mycompany:HelloWorld >----------------------
Building HelloWorld 1.0-SNAPSHOT
--------------------------------[ jar ]---------------------------------

--- exec-maven-plugin:3.0.0:exec (default-cli) @ HelloWorld ---
Exception in thread "main" java.lang.ExceptionInInitializerError
Caused by: java.lang.RuntimeException: Uncompilable code - cannot find symbol
symbol: class testArray2
location: class com.mycompany.helloworld.Main
at com.mycompany.helloworld.Main.<clinit>(Main.java:1 )
Command execution failed.
org.apache.commons.exec.ExecuteException: Process exited with an error: 1 (Exit value: 1)
at org.apache.commons.exec.DefaultExecutor.executeInt ernal (DefaultExecutor.java:404)
at org.apache.commons.exec.DefaultExecutor.execute (DefaultExecutor.java:166)
at org.codehaus.mojo.exec.ExecMojo.executeCommandLine (ExecMojo.java:982)
at org.codehaus.mojo.exec.ExecMojo.executeCommandLine (ExecMojo.java:929)
at org.codehaus.mojo.exec.ExecMojo.execute (ExecMojo.java:457)
at org.apache.maven.plugin.DefaultBuildPluginManager. executeMojo (DefaultBuildPluginManager.java:137)
at org.apache.maven.lifecycle.internal.MojoExecutor.e xecute (MojoExecutor.java:210)
at org.apache.maven.lifecycle.internal.MojoExecutor.e xecute (MojoExecutor.java:156)
at org.apache.maven.lifecycle.internal.MojoExecutor.e xecute (MojoExecutor.java:148)
at org.apache.maven.lifecycle.internal.LifecycleModul eBuilder.buildProject (LifecycleModuleBuilder.java:117)
at org.apache.maven.lifecycle.internal.LifecycleModul eBuilder.buildProject (LifecycleModuleBuilder.java:81)
at org.apache.maven.lifecycle.internal.builder.single threaded.SingleThreadedBuilder.build (SingleThreadedBuilder.java:56)
at org.apache.maven.lifecycle.internal.LifecycleStart er.execute (LifecycleStarter.java:128)
at org.apache.maven.DefaultMaven.doExecute (DefaultMaven.java:305)
at org.apache.maven.DefaultMaven.doExecute (DefaultMaven.java:192)
at org.apache.maven.DefaultMaven.execute (DefaultMaven.java:105)
at org.apache.maven.cli.MavenCli.execute (MavenCli.java:957)
at org.apache.maven.cli.MavenCli.doMain (MavenCli.java:289)
at org.apache.maven.cli.MavenCli.main (MavenCli.java:193)
at jdk.internal.reflect.NativeMethodAccessorImpl.invo ke0 (Native Method)
at jdk.internal.reflect.NativeMethodAccessorImpl.invo ke (NativeMethodAccessorImpl.java:77)
at jdk.internal.reflect.DelegatingMethodAccessorImpl. invoke (DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke (Method.java:568)
at org.codehaus.plexus.classworlds.launcher.Launcher. launchEnhanced (Launcher.java:282)
at org.codehaus.plexus.classworlds.launcher.Launcher. launch (Launcher.java:225)
at org.codehaus.plexus.classworlds.launcher.Launcher. mainWithExitCode (Launcher.java:406)
at org.codehaus.plexus.classworlds.launcher.Launcher. main (Launcher.java:347)
------------------------------------------------------------------------
BUILD FAILURE
------------------------------------------------------------------------
Total time: 1.533 s
Finished at: 2022-01-09T22:34:43-05:00
------------------------------------------------------------------------
Failed to execute goal org.codehaus.mojo:exec-maven-plugin:3.0.0:exec (default-cli) on project HelloWorld: Command execution failed.: Process exited with an error: 1 (Exit value: 1) -> [Help 1]

To see the full stack trace of the errors, re-run Maven with the -e switch.
Re-run Maven using the -X switch to enable full debug logging.

For more information about the errors and possible solutions, please read the following articles:
[Help 1] http://cwiki.apache.org/confluence/d...utionException

Originally Posted by Norm

That assignment statement needs to be inside of a method.
Only initialization statements can be outside of a method.

Makes sense. But I vaguely remember, from long ago, that in a class definition you could use

static
{
   // arbitrary code here
}

for code to be executed at class load time.

Originally Posted by Norm

That assignment statement needs to be inside of a method.
Only initialization statements can be outside of a method.

Thank you. That worked but I still don't know what I'm doing so I need to experiment. I still don't understand why no online courses or examples work out of the box. It's difficult to learn something when you can't even follow along with lessons because you are forced to go off on tangents to learn non documented material when you are doing simple beginner lessons.