Java converts string to double using Double.parseDouble(String)
package com.w3schools;
public class StringToDouble {
  public static void main(String args[]){
	String str="546.307";
	//convert String to double
	double var= Double.parseDouble(str);
	System.out.println(var);
  }
}
Output
546.307
 
Java converts string to double using Double.valueOf(String)
package com.w3schools;
public class StringToDouble {
  public static void main(String args[]){
	String str="546.307";
	//convert String to double
	double var= Double.valueOf(str);
	System.out.println(var);
  }
}
Output
546.307