Can't resolve methods in Java class for Temperature Driver -

***i'm having issues creating add() subtract() , divide() method, maybe i'm overthinking it. how return needed object. ide saying "cannot resolve symbol temperature". calling 'this' correctly?

***i aware add , divide methods incomplete, if can receive on completing subtract() method should fall place.

    import javax.naming.stringrefaddr;  /**  * created makoto on 2/4/2016.  */  public class temperature {     public double temp;     public char type;      temperature() {         temp = 0.0;         type = 'o';      }      temperature( double temperature, char temptype){             temperature = temp;             temptype = type;     }      public temperature tofahrenheit() {         type.equalsignorecase();         switch (type) {             case 'c':                  break;              case 'k':                  break;              default:                 system.out.println("can not convert.");                 break;         }          return this.temperature;     }      public temperature tocelsius() {         type.equalsignorecase();         switch (type) {             case 'f':                  break;              case 'k':                  break;              default:                 system.out.println("can not convert.");                 break;         }          return this.temperature;     }      public temperature tokelvin() {         type.equalsignorecase();         switch (type) {             case 'c':                  break;              case 'f':                  break;              default:                 system.out.println("can not convert.");                 break;         }          return this.temperature;     }      public temperature add(temperature x){          this.temperature + x;         return this.temperature;     }      public temperature subtract(temperature x){          this.temperature = this.temp - x.temp;         return this.temperature;     }     public temperature divide(int x){          this.temperature = /x;         return this.temperature;     }  } 

you need return only.

  import javax.naming.stringrefaddr;  /**  * created makoto on 2/4/2016.  */  public class temperature {     public double temp;     public char type;      temperature() {         temp = 0.0;         type = 'o';      }      temperature( double temperature, char temptype){             temperature = temp;             temptype = type;     }      public temperature tofahrenheit() {         type.equalsignorecase();         switch (type) {             case 'c':                  break;              case 'k':                  break;              default:                 system.out.println("can not convert.");                 break;         }          return this;     }      public temperature tocelsius() {         type.equalsignorecase();         switch (type) {             case 'f':                  break;              case 'k':                  break;              default:                 system.out.println("can not convert.");                 break;         }          return this;     }      public temperature tokelvin() {         type.equalsignorecase();         switch (type) {             case 'c':                  break;              case 'f':                  break;              default:                 system.out.println("can not convert.");                 break;         }          return this;     }      public temperature add(temperature x){          this.temp + x.temp;         return this;     }      public temperature subtract(temperature x){          this.temp = this.temp - x.temp;         return this;     }     public temperature divide(int x){          this.temp = /x;         return this;     }  }