import java.util.regex.Matcher;
import java.util.regex.Pattern;

class SearchAndReplace{
	public static void main(String[] args){
		String regEx = "dog";
		String str = "My dog hasm't got any nose.\n"
				+ "How does your dog smell then?\n"
				+ "My dog smells horrible.\n";
		
		Pattern pattern = Pattern.compile(regEx);
		Matcher m = pattern.matcher(str);
		
		StringBuffer sb = new StringBuffer();
		while(m.find()){
			m.appendReplacement(sb, "goat");
		}
		
		m.appendTail(sb);
		System.out.println("before:");
		System.out.println(str);
		
		System.out.println("after:");
		System.out.println(sb);
	}
}