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 # setFileExtension

 Last update: 30.07.2026 

public [setFileExtension](set-file-extension.md)(ext: [String](https://docs.oracle.com/javase/8/docs/api/java/lang/String.html), index: [String](https://docs.oracle.com/javase/8/docs/api/java/lang/String.html))

sets the desired file extension for the file

#### Parameters

extthe file extension, e.g. ".xls"indexindex in string form, i.e. \[1\]\[2\]\[3\]#### Throws

[ModelCenterException](./../-model-center-exception/index.md)public [setFileExtension](set-file-extension.md)(ext: [String](https://docs.oracle.com/javase/8/docs/api/java/lang/String.html), d1: [Long](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-long/index.html))

sets the desired file extension for the file

#### Parameters

extthe file extension, e.g. ".xls"d1index in the 1st dimension (0-based index)#### Throws

[ModelCenterException](./../-model-center-exception/index.md)public [setFileExtension](set-file-extension.md)(ext: [String](https://docs.oracle.com/javase/8/docs/api/java/lang/String.html), d1: [Long](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-long/index.html), d2: [Long](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-long/index.html))

sets the desired file extension for the file

#### Parameters

extthe file extension, e.g. ".xls"d1index in the 1st dimension (0-based index)d2index in the 2nd dimension (0-based index)#### Throws

[ModelCenterException](./../-model-center-exception/index.md)public [setFileExtension](set-file-extension.md)(ext: [String](https://docs.oracle.com/javase/8/docs/api/java/lang/String.html), d1: [Long](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-long/index.html), d2: [Long](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-long/index.html), d3: [Long](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-long/index.html))

public [setFileExtension](set-file-extension.md)(ext: [String](https://docs.oracle.com/javase/8/docs/api/java/lang/String.html), d1: [Long](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-long/index.html), d2: [Long](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-long/index.html), d3: [Long](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-long/index.html), d4: [Long](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-long/index.html))

public [setFileExtension](set-file-extension.md)(ext: [String](https://docs.oracle.com/javase/8/docs/api/java/lang/String.html), d1: [Long](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-long/index.html), d2: [Long](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-long/index.html), d3: [Long](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-long/index.html), d4: [Long](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-long/index.html), d5: [Long](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-long/index.html))

public [setFileExtension](set-file-extension.md)(ext: [String](https://docs.oracle.com/javase/8/docs/api/java/lang/String.html), d1: [Long](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-long/index.html), d2: [Long](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-long/index.html), d3: [Long](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-long/index.html), d4: [Long](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-long/index.html), d5: [Long](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-long/index.html), d6: [Long](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-long/index.html))

public [setFileExtension](set-file-extension.md)(ext: [String](https://docs.oracle.com/javase/8/docs/api/java/lang/String.html), d1: [Long](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-long/index.html), d2: [Long](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-long/index.html), d3: [Long](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-long/index.html), d4: [Long](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-long/index.html), d5: [Long](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-long/index.html), d6: [Long](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-long/index.html), d7: [Long](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-long/index.html))

public [setFileExtension](set-file-extension.md)(ext: [String](https://docs.oracle.com/javase/8/docs/api/java/lang/String.html), d1: [Long](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-long/index.html), d2: [Long](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-long/index.html), d3: [Long](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-long/index.html), d4: [Long](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-long/index.html), d5: [Long](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-long/index.html), d6: [Long](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-long/index.html), d7: [Long](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-long/index.html), d8: [Long](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-long/index.html))

public [setFileExtension](set-file-extension.md)(ext: [String](https://docs.oracle.com/javase/8/docs/api/java/lang/String.html), d1: [Long](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-long/index.html), d2: [Long](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-long/index.html), d3: [Long](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-long/index.html), d4: [Long](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-long/index.html), d5: [Long](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-long/index.html), d6: [Long](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-long/index.html), d7: [Long](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-long/index.html), d8: [Long](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-long/index.html), d9: [Long](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-long/index.html))

public [setFileExtension](set-file-extension.md)(ext: [String](https://docs.oracle.com/javase/8/docs/api/java/lang/String.html), d1: [Long](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-long/index.html), d2: [Long](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-long/index.html), d3: [Long](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-long/index.html), d4: [Long](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-long/index.html), d5: [Long](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-long/index.html), d6: [Long](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-long/index.html), d7: [Long](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-long/index.html), d8: [Long](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-long/index.html), d9: [Long](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-long/index.html), d10: [Long](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-long/index.html))