I get the message "90: error: missing return statement" when trying to compile this cod

The line that it's referencing is just a curly bracket.

Code:
class Persons	{

//Declare instance variables

	private String name;
	private String nationality;
	private int age;
	private int steps;
	private int weight;
	private int height;

//Declare getter and setter methods

	public String getName()	{
		return name;
	}


	public String getNationality()	{
		return nationality;
	}


	public int getAge()	{
		return age;
	}


	public int getSteps()	{
		return steps;
	}


	public int getWeight()	{
		return weight;
	}


	public int getHeight()	{
		return height;
	}


	public String setName(String n)	{
		name = n;
		return n;
	}
	
	
	public String setNationality(String z)	{
		nationality = z;
		return z;
	}


	public void setAge(int a)	{
		age = a;
	}


	public void setSteps(int s)	{
		steps = s;
	}

	public void setWeight(int w)	{
		weight = w;
	}

	public void setHeight(int h)	{
		height = h;
	}

	
//Method that evaluates string value and prints applicable value

	public String talk()	{

	if (nationality == "American")	{
		System.out.println("They speak English.");
	}

	else if (nationality == "German")	{
		System.out.println("They speak German.");
	}

	else {
		System.out.println("Unknown spoken language.");
	}

      	}

//Method that prints what's in the println statement the applicable number of times 

based on the value of steps.

	public void walk()	{
		int x = 1;
		while (x < steps) {
			System.out.println("I'm walking.");
			x = x + 1;
		}		
	
	}

//Performs the calculation based on the weight and height values passed to it.
	public int calcBMI()	{
		int bmi = weight / height;
		return bmi;
	}
		
}

  class PersonsTestDrive	{

	public static void main (String[] args)	{


		Persons[] myHuman;
		myHuman = new Persons[2];

		myHuman[0] = new Persons();
		

		  myHuman[0].setName("Joe");
		  myHuman[0].setNationality("American");
		  myHuman[0].setAge(30);
	          myHuman[0].setSteps(4);	
		  
 			System.out.println("Person one's name:" + 			

			myHuman[0].getName());

			System.out.println("Person one's nationality:" + 		

			myHuman[0].getNationality());
		
			System.out.println("Person one's age:" + 			

			myHuman[0].getAge());

			myHuman[0].talk();
			myHuman[0].walk();

		myHuman[1] = new Persons();	

		  myHuman[1].setName("Ingrid");
		  myHuman[1].setNationality("German");
		  myHuman[1].setAge(35);
		  myHuman[1].setSteps(2);
		  myHuman[1].setWeight(125);
		  myHuman[1].setHeight(60);
		
			System.out.println("Person two's name:" + 			

			myHuman[1].getName());

			System.out.println("Person two's nationality:" + 		

			myHuman[1].getNationality());

			System.out.println("Person two's age:" + 			

			myHuman[1].getAge());

			myHuman[1].talk();
			myHuman[1].walk();

			System.out.println("Person two's Body Mass 			

			Index is:" + myHuman[1].calcBMI());
	}

}