If you are using Groovy, it's likely that you unintentionally added the `private` modifier to a property declaration:

```groovy
@InputFile
RegularFileProperty inputFile // this is a public property

@InputFile
private RegularFileProperty inputFile // this is a field, remove the `private` modifier
```

[[ignored_annotations_on_method]]
== Invalid annotation on method

                File outputFile

                @InputFile
                @PathSensitive(PathSensitivity.NONE)
                File inputFile

                @TaskAction
                public void makeOutput() {
                    outputFile.text = "done"
                }
            }

            task cacheable(type: CustomTask) {
                inputFile = file("input")

    @SuppressWarnings("GrDeprecatedAPIUsage")
    static class SimpleTask extends DefaultTask {
        @Input
        String inputString
        @InputFile
        File inputFile
        @InputDirectory
        File inputDirectory
        @InputFiles
        File inputFiles
        @OutputFile
        File outputFile
        @OutputFiles
        Set<File> outputFiles
        @OutputDirectory

package com.example;

import org.gradle.api.DefaultTask;
import org.gradle.api.file.RegularFileProperty;
import org.gradle.api.provider.ListProperty;
import org.gradle.api.tasks.InputFile;
import org.gradle.api.tasks.Internal;
import org.gradle.api.tasks.PathSensitive;
import org.gradle.api.tasks.PathSensitivity;
import org.gradle.api.tasks.TaskAction;

import java.io.IOException;
import java.nio.file.Files;
import java.util.regex.Pattern;

import org.gradle.api.internal.AbstractBuildableComponentSpec;
import org.gradle.api.tasks.IgnoreEmptyDirectories;
import org.gradle.api.tasks.Input;
import org.gradle.api.tasks.InputFile;
import org.gradle.api.tasks.InputFiles;
import org.gradle.api.tasks.Internal;
import org.gradle.api.tasks.Optional;
import org.gradle.api.tasks.PathSensitive;
import org.gradle.api.tasks.PathSensitivity;

        <title>Properties</title>
        <table>
            <thead>
                <tr>
                    <td>Name</td>
                </tr>
            </thead>
            <tr>
                <td>inputFile</td>
            </tr>
            <tr>
                <td>outputFile</td>
            </tr>
        </table>
    </section>
    <section>
        <title>Methods</title>
        <table>

 */
public abstract class PersistableConfigurationObjectGenerator<T extends PersistableConfigurationObject> implements Generator<T>, Factory<T> {
    @Override
    public T read(File inputFile) {
        T obj = create();
        obj.load(inputFile);
        return obj;
    }

    @Override
    public T defaultInstance() {
        T obj = create();
        obj.loadDefaults();
        return obj;
    }

     *
     * @since 4.3
     */
    // TODO - allow @InputFile and @SkipWhenEmpty to be attached to getExecutableFile()
    @SkipWhenEmpty
    @Nullable
    @Optional
    @PathSensitive(PathSensitivity.NAME_ONLY)
    @InputFile
    protected File getInputFileIfExists() {
        RegularFileProperty sourceFile = getExecutableFile();

                def outputFile = file('build/output.txt')
                def inputFile = file('input.txt')
                inputs.file inputFile
                inputs.file 'unrelated-input.txt'
                outputs.file outputFile
                outputs.cacheIf { true }
                doLast {
                    if (!outputFile.exists() || outputFile.text != inputFile.text) {
                        outputFile.parentFile.mkdirs()

    }

    @Override
    public void transformAction(Action<? super XmlProvider> action) {
        delegate.transformAction(action);
    }

    @Override
    public void load(File inputFile) {
        delegate.load(inputFile);
    }

    @Override
    public void loadDefaults() {
        delegate.loadDefaults();
    }

    @Override
    public void store(File outputFile) {