Why is the result different

Question

**the only different point is whether or not the construct function has "void
"keyword,but the result is completely different,who can give me an answer ,thanks.
*the result: a[1234]=0
public class SynTest4
static int a[]=new int[10000];
public void SynTest4()
synchronized(a)
for (int i=0; i<10000; i++) { a[i]=i; }
public static void main(String[] args)
new SynTest4();
System.out.println("a[1234]= "+a[1234]);
*the result:a[1234]=1234
public class SynTest4
static int a[]=new int[10000];
public SynTest4()
synchronized(a)
for (int i=0; i<10000; i++) { a[i]=i; }
public static void main(String[] args)
new SynTest4();
System.out.println("a[1234]= "+a[1234]);
}

Answer 1

A constructor has no return type. If you create a method with a return type, it is not a constructor. If you create a class without a constructor, the compiler will automatically create a default constructor.
So, your "public void SynTest4()" is a normal method, not a constructor.