can anyone help me with this debugging assignment for java i keep getting the same two errors

/*

Chapter 9: UserList solution

Programmer:

Date: August 28, 2017

Filename: UserList.java

Purpose: Builds a list of user names

*/

public class UserList

{

public static void main(String[] args) throws Exception

{

String str1, str2 = "username";

int index;

int initialCapacity = 10;

BufferedReader dataIn = new

BufferedReader(new

InputStreamReader(System.in));

ArrayList users = new ArrayList();

System.out.print("Enter a user name: ");

str1 = dataIn.readLine();

while(str1.length() > 0)

{

if(str1 == str2);

System.out.println("That user name is NOT allowed!");

else

{

if(users.size() == initialCapacity)

{

System.out.println("List is full!");

System.out.println("Last entry is "+users.get(initialCapacity));

}

else

{

if(!users.contains(str1))

{

users.add(str1);

System.out.println("User \""+str1+"\" added to user list.");

}

else

System.out.println("User \""+str1+"\" already in user list.");

}

System.out.print(" Enter a user name: ");

str1 = dataIn.readLine();

}

System.out.println("Program complete.");

}

}

these are the error messages