Groovy and Java classes

Any Groovy or Java class that is available to Nextflow at runtime can be used in a Nextflow script. The following classes are imported by default:

• groovy.lang.*

• groovy.util.*

• java.io.*

• java.lang.*

• java.math.BigDecimal

• java.math.BigInteger

• java.net.*

• java.util.*

All other classes must be referenced by their fully-qualified name:

def vals = [1, 2, 3]
println groovy.json.JsonOutput.toJson(vals)

Note

The set of classes in Nextflow’s runtime classpath can change between different Nextflow versions. As a best practice, any code that uses classes outside the Nextflow standard library should either be refactored to only use the Nextflow standard library or be refactored as a plugin with explicit dependencies.