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    <p>your if statement is jacked up:</p> <pre><code>if(Verzameling.a.elementen[i] = Verzameling.b.elementen[j]) </code></pre> <p>you are doing assignment, you are not testing anything.</p> <p>try</p> <pre><code>Verzameling.a.elementen[i].equals(Verzameling.b.elementen[j]) </code></pre> <p>or </p> <pre><code>Verzameling.a.elementen[i] == Verzameling.b.elementen[j] </code></pre> <p>note that you will need to make sure Verzameling.a.elementen[i] is not null if you use the equals method. Also note that for numbers == is ok, but for objects you want to use equals unless you are sure you want == (== means something very specific for objects)</p> <p>PREEDIT --</p> <p>Your code is not compiling for a few reasons. The first of which is that your a and b variables are declared in the scope of main, so they are only accessible in main. Moving them up to the class and making them public and static means they can be accessed from anywhere.</p> <p>EDIT -- I can't believe Im doing someone's homework, but -- this does not work, but at least it compiles</p> <pre><code>import java.util.Random; public class opgave6 { public static Verzameling a = new Verzameling(20, 3); public static Verzameling b = new Verzameling(20, 4); public static void main(String[] args) { System.out.println("before something"); System.out.println(Verzameling.deelverzamelingVan()); System.out.println("after something"); } } class Verzameling { int[] elementen; int elementen2; static int aantal2; Verzameling(int aantal, int seed) { elementen = new int[100]; int aantal2 = aantal; for (int i = 0; i &lt; 100; i++) { elementen[i] = i; } Random random1 = new Random(seed); for (int i = 0; i &lt; 100; i++) { int r = random1.nextInt(100); int temp; temp = elementen[i]; elementen[i] = elementen[r]; elementen[r] = temp; } printVerzameling(aantal); } // you arent using it -- do so or delete it Verzameling(int seed) { } void printVerzameling(int aantal) { for (int i = 0; i &lt; aantal; i++) { System.out.print(elementen[i] + " "); } System.out.println(); } static boolean deelverzamelingVan() { for (int i = 0; i &lt; aantal2; i++) { for (int j = 0; j &lt; aantal2; j++) { int aElementen = opgave6.a.elementen[i]; int bElementen = opgave6.b.elementen[j]; System.out.println(String.format("Comparing a[i] to b[i] [%d, %d]", aElementen, bElementen)); if (aElementen == bElementen) break; } } // need to return something, i dont know what. return true; } } </code></pre>
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    1. COthanks for the comment, however it is still erroring when i compile. It says it cannot find symbol about verzameling.a.elementen, i, verzameling.b.elementen and j. I think i am naming it wrong, is it ok to call the variable by saying: classname.objectname.variable of object?
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    2. CO@javaaaa if the object is static and the variable is public
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    3. COthe object cant be static right? the method static boolean deelVerzameling is static, but objects cant be static per definition right?
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