"IllegalFormatConversionException: d != java.lang.String" when padding number with 0s?

Question

I had a perfectly working code yesterday, in the exact form of:

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int lastRecord = 1;
String key = String.format("%08d", Integer.toString(lastRecord));

Which would pad it nicely to 00000001.

Now I kicked it up a notch with twoKeyChar getting a string from a table and lastRecord getting an int from a table.

As you can see the concept is essentially the same - I convert an int to a string and try to pad it with 0s; however, this time I get the following error:

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java.util.IllegalFormatConversionException: d != java.lang.String

The code is below:

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String newPK = null;
String twoCharKey = getTwoCharKey(tablename);
if (twoCharKey != null) {
     int lastRecord = getLastRecord(tablename);
     lastRecord++;
     //The println below outputs the correct values: "RU" and 11. 
     System.out.println("twocharkey:"+twoCharKey+"record:"+lastRecord+"<");
     //Now just to make it RU00000011
     newPK = String.format("%08d", Integer.toString(lastRecord));
     newPK = twoCharKey.concat(newPK);
}

I feel like I must have typed something wrong, because there is no reason for it to break since the last time when it worked. Any help/hint is appreciated! Thank You!

Answer 1

You don't need the Integer.toString():

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 newPK = String.format("%08d", lastRecord);

String.format() will do the conversion and the padding.

Answer 2

It worked for me, It should be integer here 12 should be integer.

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String.format("%04d", Integer.parseInt("12"));

output - 0012

Answer 3

Very late to the party.

If you still are facing an issue to the String.format(); code even after implementing accepted answer.

This did not work for me:

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String.format("%08d", stringvariable);

Because of two reasons:

1. It will not work as d will expect for decimal point not string.
2. Use %8d instead of %08d as formatter did not work for me if I used this %08d

If you are using String based Variable with String data. Use this.

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String.format("%8s", stringvariable);

Answer 4

I our case with this problem it was do to java/kotlin conversion issue handling vargs because we had wrapped resources in a Kotlin file, where the missing trick was the flattern * operator

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class LocalizedResources @Inject constructor(
    @ApplicationContext context: Context
) {
    private val resources = LokaliseResources(context)

    fun getString(@StringRes resId: Int): String {
        return resources.getString(resId)
    }

    fun getString(@StringRes resId: Int, vararg formatArgs: Any?): String {
        return resources.getString(resId, *formatArgs)
    }
}