Switch Statement gives Incompatible Types error

Question

I am trying to compile and I get this error:

enigma/Rotor.java:30: incompatible types found : java.lang.String required: int     switch(name){
1 error

Why am I getting this error? How do I fix it? It's in the package and I can't seem to figure it out. Here's the code:

String label;

Rotor(){;}

Rotor(String name){
  switch(name){
    case "B":
      conversion_chart = B;
      break;
    case "C":
      conversion_chart = C;
      break;
    case "I":
      conversion_chart=I;
      notch = NOTCH[0];
      break;
    case "II":
      conversion_chart=II;
      notch = NOTCH[1];
      break;
    case "III":
      conversion_chart=III;
      notch = NOTCH[2];
      break;
    case "IV":
      conversion_chart=IV;
      notch = NOTCH[3];
      break;
    case "V":
      conversion_chart=V;
      notch = NOTCH[4];
      break;
    case "VI":
      conversion_chart=VI;
      notch = NOTCH[5];
      break;
    case "VII":
      notch = NOTCH[6];
      conversion_chart=VII;
      break;
    case "VIII":
      notch = NOTCH[7];
      conversion_chart=VIII;
      break;
  }
  label = name;
  position = 0;
}

score 11 · Answer 1 · edited Nov 25 '20 at 10:04

11

switch(name)

switch statement with String is supported from Java7 onwards only.

I guess the compiler version you are using is less than Java7

Options:

You need to either upgrade to Java7
Change switch statement to if/else
Use int in switch instead of String

edited Nov 25 '20 at 10:04

MC Emperor

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answered Sep 20 '12 at 21:43

kosa

65,990
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1

You need to upgrade your java to Java7 – kosa Sep 20 '12 at 21:44
And if this still fails, it could be your IDE. For intelliJ, go to `File > Project Structure > Project > Project Language Level` and set to 7 and above – mugume david Jun 26 '15 at 06:36

score 6 · Answer 2 · answered Jul 25 '18 at 15:57

6

If you are using maven project then simply you can add following piece of code to ypur pom.xml and resolve your problem :

 <build>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <configuration>
                    <source>1.8</source>
                    <target>1.8</target>
                </configuration>
            </plugin>
        </plugins>
    </build>

answered Jul 25 '18 at 15:57

Suraj Jogdand

308
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Looks like Maven stuck in medieval times. I had never ever thought that such obvious thing like standard java API should be enabled explicitly by adding some lines in maven pom file. It works tho, thanks! – Kirill Karmazin Dec 28 '18 at 17:06

PermGenError · Answer 3 · 2013-05-16T14:30:22.670

4

switch accepts a String from java 7. prior to java 7 only int compatible types (short,byte,int, char) can be passed as switch arguments

edited May 16 '13 at 14:30

answered Sep 20 '12 at 21:45

PermGenError

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I'm really sorry about that. I have been trying to remove this downvote and it tells me I'm not allowed to change my vote. It was an accidental downvote, is there an undo? – krico May 16 '13 at 14:27
@krico i have just edited my post, you can now revert your downvote .. :) – PermGenError May 16 '13 at 14:30

score 1 · Answer 4 · edited Jul 02 '21 at 10:20

1

If you're using maven then change build in pom as following else change JDK version as 1.8+

<plugin>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven-compiler-plugin</artifactId>
    <configuration>
        <source>1.8</source>
        <target>1.8</target>
    </configuration>
</plugin>

edited Jul 02 '21 at 10:20

b.s

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answered Jul 01 '21 at 09:22

zjf

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score 0 · Answer 5 · answered Sep 20 '12 at 21:44

0

You cannot switch over a String instance, only int (and byte/char/short, but not long/double), unless you have Java7+. Your best option now is to change to if else statements, like so:

if("B".equals(string)) {
    //handle string being "B"
} else if("C".equals(string)) {
    //handle string being "C"
} else ...

For more info on switching, see the Oracle tutorial. They mention the Java7 String functionality:

In Java SE 7 and later, you can use a String object in the switch statement's expression.

answered Sep 20 '12 at 21:44

Alex Coleman

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@user1514362 What do you mean? I gave you an example which doesn't use a switch statement but perfoms the same thing. Isn't this what you want? You must remove your switch statement to make it work – Alex Coleman Sep 20 '12 at 21:49

score -1 · Answer 6 · answered Sep 20 '12 at 21:44

-1

In Java, you can only do a switch on byte, char, short, or int, and not a String.

answered Sep 20 '12 at 21:44

Don Branson

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Unless you are using Java 7 or newer - see other answers. – Windle Sep 20 '12 at 21:46

Switch Statement gives Incompatible Types error

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