java - Copy 2D array within object by reference -

object1.java:

public class object1 {     public double[][] var1;     ... } 

object2.java:

public class object2 {     public double[][] var2;     ... } 

i want copy reference (shallow copy) object2.var2 object1.var1. here's i'm trying, isn't working:

 object1 object1 = new object1();  object1.var1 = new double[2][];  system.arraycopy(object2.var2, 0, object1.var1, 0, object2.var2.length); 

anyone know i'm going wrong? i'm getting java.lang.nullpointerexception compile error. note object2.var2 populated data.

update 1:

note object2.var2 nx2 matrix, looks like:

object2.var2[0][0]=1.232 object2.var2[0][1]=23.233 object2.var2[1][0]=3.23 object2.var2[1][1]=32.12 ... object2.var2[n][0]=3.23 object2.var2[n][1]=32.12 

i see java.lang.nullpointerexception when try following:

object1.var1=new double[object2.var2.length][2]; object1.var1=object2.var2; 

    object2 object2 = new object2();         // need iniialize ur object2.var2 first     object2.var2 = new double[][]{ {1.232, 23.233},{3.23,32.12},{3.23,32.12}};     //or      object2.var2 = new double[3][2];     object2.var2[0][0]=1.232;     object2.var2[0][1]=23.233;     object2.var2[1][0]=3.23;     object2.var2[1][1]=32.12;     object2.var2[2][0]=3.23;     object2.var2[2][1]=32.12;      system.out.println(object2.var2);     object1 object1 = new object1();     object1.var1= new double[object2.var2.length][2];     system.out.println(object1.var1);     system.arraycopy(object2.var2, 0, object1.var1, 0, object2.var2.length);