Android Studio编译报错：无法识别Java 11新增的Files.writeString与Files.readString方法

Got it, since you've already tried common fixes like invalidating caches, deleting .idea/.gradle folders, and letting Android Studio download its own Java 11, here are more targeted troubleshooting steps to resolve the writeString/readString compilation error:

• Verify Project & Module Java Version Configurations
  Open File > Project Structure and double-check these settings:

  • Under Project, confirm the Project SDK is set to Java 11.
  • Navigate to Modules > [Your App Module] > Sources, set the Language level to 11 (Lambda expressions, type annotations etc.) or higher.
  • Go to Modules > [Your App Module] > Dependencies, ensure the Module SDK matches either Java 11 or an Android API level that supports Java 11 features (API 30+).

• Update Module-level build.gradle Configurations
  Make sure your app's build.gradle explicitly enables Java 11 compatibility:

  android {
      compileSdkVersion 34 // Use API 30 or higher for Java 11 support
      defaultConfig {
          // ... other configs
      }
  
      compileOptions {
          sourceCompatibility JavaVersion.VERSION_11
          targetCompatibility JavaVersion.VERSION_11
      }
  
      // If using Kotlin, add this to align JVM target
      kotlinOptions {
          jvmTarget = "11"
      }
  }
  

• Check Gradle Plugin & Wrapper Versions
  Older Gradle versions lack full Java 11 support. Update your project-level build.gradle to use a compatible plugin version (7.0+):

  buildscript {
      dependencies {
          classpath "com.android.tools.build:gradle:7.4.2" // Or a newer stable version
      }
  }
  

  Also, confirm the Gradle wrapper in gradle/wrapper/gradle-wrapper.properties matches:

  distributionUrl=https\://services.gradle.org/distributions/gradle-7.4.2-bin.zip
  

• Validate System Java Environment
  Even if you removed Java 8, check if your system's environment variables are pointing to Java 11. Open Android Studio's Terminal and run:

  java -version
  javac -version
  

  Both should output Java 11.x. If not, update your JAVA_HOME and PATH to point to your Java 11 installation.

• Check Compile SDK Version Compatibility
  Android only supports Java 11 language features when using compileSdkVersion 30 or higher. Double-check this setting in your app's build.gradle—using an older SDK version will block access to Java 11-specific methods.

• Test with a Fresh Project
  Create a new empty Android project, configure it for Java 11, and paste your file I/O code. If it compiles successfully, the issue is likely tied to your original project's custom configurations, dependency conflicts, or corrupted module settings. You can then gradually migrate your original project's code/configs to the new project to isolate the problem.

内容的提问来源于stack exchange，提问作者Kokufuu