How does Gradle's build script (build.gradle / build.gradle.kts) differ structurally from Maven's declarative XML pom.xml?

Maven's pom.xml is a purely declarative XML document describing what the project needs (dependencies, plugins, configuration), with the actual build logic entirely hidden inside Maven's plugin implementations; Gradle's build.gradle (Groovy DSL) or build.gradle.kts (Kotlin DSL) is instead an actual executable script, giving you a full general-purpose programming language to express custom build logic directly, imperative task definitions, and conditional configuration -- this makes Gradle more flexible and often more concise for complex, non-standard build requirements, at the cost of build scripts potentially becoming harder to reason about if that flexibility gets over-used.

// build.gradle.kts (Kotlin DSL)
plugins {
    id("java")
}

dependencies {
    implementation("com.fasterxml.jackson.core:jackson-databind:2.15.2")
    testImplementation("org.junit.jupiter:junit-jupiter:5.10.0")
}

tasks.test {
    useJUnitPlatform()
}