Suspicious '::javaClass' callable reference

Reports suspicious cases of kotlin.jvm.javaClass extension used as a callable reference.

Using ::javaClass syntax does not result in a Class<T> instance, as someone might expect.

Instead, it creates a property reference of type KProperty0<Class<T>>, which is almost never correct and can lead to unexpected behavior and hard-to-detect bugs.

Provides a fix to use a direct .javaClass call or ::class.java syntax instead.

Example 1: Expression receiver

When ::javaClass is used on an expression, the quick-fix replaces it with a regular .javaClass call:

  fun test(a: String) {
      val classRef = a::javaClass  // KProperty0<Class<String>>
      println(classRef)            // Prints "property javaClass", not "class java.lang.String"
  }

  fun test(a: String) {
      val classRef = a.javaClass  // Class<String>
      println(classRef)           // Prints "java.lang.String"
  }

Example 2: Type receiver

When ::javaClass is used on a type, the quick-fix replaces it with ::class.java:

  fun test() {
      val classRef = String::javaClass  // KProperty1<String, Class<String>>
      println(classRef)                 // Prints "property javaClass", not "class java.lang.String"
  }

  fun test() {
      val classRef = String::class.java  // Class<Any>
      println(classRef)                  // Prints "class java.lang.String"
  }

Locating this inspection

By ID

Can be used to locate inspection in e.g. Qodana configuration files, where you can quickly enable or disable it, or adjust its settings.

SuspiciousJavaClassCallableReference

Via Settings dialog

Path to the inspection settings via IntelliJ Platform IDE Settings dialog, when you need to adjust inspection settings directly from your IDE.

Settings or Preferences | Editor | Inspections | Kotlin | Probable bugs

Inspection ID: SuspiciousJavaClassCallableReference

Suppressing Inspection

You can suppress this inspection by placing the following comment marker before the code fragment where you no longer want messages from this inspection to appear:

//noinspection SuspiciousJavaClassCallableReference

More detailed instructions as well as other ways and options that you have can be found in the product documentation:

IntelliJ IDEA 2026.1

Inspection Details
By default bundled with:	IntelliJ IDEA 2026.1, Qodana for JVM 2026.1,

Last modified: 31 March 2026