How to Resolve 'Fatal Error: Unable to Find Package java.lang in Classpath or Bootclasspath' in Gradle with Retrolambda

What steps can I take to resolve the 'Fatal Error: Unable to find package java.lang in classpath or bootclasspath' when using Gradle and Retrolambda?

// Example of using Retrolambda in build.gradle
android {
    compileOptions {
        sourceCompatibility JavaVersion.VERSION_1_8
        targetCompatibility JavaVersion.VERSION_1_8
    }
}

The error 'Fatal Error: Unable to find package java.lang in classpath or bootclasspath' typically occurs in Android projects that use Gradle and Retrolambda for enabling Java 8 features. This issue arises due to misconfiguration in the project setup, particularly in the java version settings or the Retrolambda plugin.

apply plugin: 'me.tatarka.retrolambda'

retrolambda {
    jdk 'path/to/jdk'
    oldVersion '1.7'
    newVersion '1.8'
    javaVersion JavaVersion.VERSION_1_8
}

Causes

• Incorrect Java version setup in build.gradle
• Missing or misconfigured Retrolambda plugin
• Incompatible versions of Gradle and Android plugin

Solutions

• Ensure that you have installed the correct version of Java Development Kit (JDK 8).
• Verify that your build.gradle file includes the correct compile options for Java 8.
• Make sure Retrolambda is correctly applied in your build.gradle, check for syntax errors.

Mistake: Using a Java version higher than 8 while Retrolambda only supports up to Java 8.

Solution: Ensure JDK 8 is being used for your Android project.

Mistake: Not specifying the correct path to the JDK in the Retrolambda configuration.

Solution: Double-check the jdk path in your Retrolambda block in build.gradle.