Following is a simple program to print first n Fibonacci numbers in java.

Examples : 

Input : n = 3
Output : 0 1 1

Input : n = 7
Output : 0 1 1 2 3 5 8

IN JAVA:

// Java program to print
// first n Fibonacci Numbers

class Test {
	// Method to print
	// first n Fibonacci Numbers
	static void printFibonacciNumbers(int n)
	{
		int f1 = 0, f2 = 1, i;

		if (n < 1)
			return;
		System.out.print(f1 + " ");
		for (i = 1; i < n; i++)
		{
			System.out.print(f2 + " ");
			int next = f1 + f2;
			f1 = f2;
			f2 = next;
		}
	}

	// Driver Code
	public static void main(String[] args)
	{
		printFibonacciNumbers(7);
	}
}

Output

0 1 1 2 3 5 8 

Time Complexity: O(n)