Pass a string to the Integer class constructor and call the intValue() : Data Type Conversion « Data Type « Java Tutorial

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3. Data Type Conversion

public class Main {
  public static void main(String[] argv) {

    String sValue = "5";

    try {
      int iValue = new Integer(sValue).intValue();
    } catch (NumberFormatException ex) {
      ex.printStackTrace();
    }
  }
}