Please get checker-qual and error_prone_annotations to agree with caffeine...update your check-qual dependency to 2.6.0 and your error_prone_annotations dependency to 2.3.3, please.

    Require upper bound dependencies error for org.checkerframework:checker-qua>
        +-com.google.guava:guava:27.1-jre (managed) <-- com.google.guava:guava:>
          +-org.checkerframework:checker-qual:2.5.2
    and
        +-com.github.ben-manes.caffeine:caffeine:2.7.0
          +-org.checkerframework:checker-qual:2.6.0

    Require upper bound dependencies error for com.google.errorprone:error_pron>
        +-com.google.guava:guava:27.1-jre (managed) <-- com.google.guava:guava:>
          +-com.google.errorprone:error_prone_annotations:2.2.0
    and
        +-com.github.ben-manes.caffeine:caffeine:2.7.0
          +-com.google.errorprone:error_prone_annotations:2.3.3

public void testGet_usePublicConstant() {
    assertSame(WithPublicConstant.INSTANCE, ArbitraryInstances.get(WithPublicConstant.class));
  }
  public void testGet_useFirstPublicConstant() {
    assertSame(WithPublicConstants.FIRST, ArbitraryInstances.get(WithPublicConstants.class));
  }
  public void testGet_nullConstantIgnored() {
    assertSame(FirstConstantIsNull.SECOND, ArbitraryInstances.get(FirstConstantIsNull.class));
  }
  public void testGet_constantWithGenericsNotUsed() {
    assertNull(ArbitraryInstances.get(WithGenericConstant.class));
  }
  public void testGet_nullConstant() {
    assertNull(ArbitraryInstances.get(WithNullConstant.class));
  }
  public void testGet_constantTypeDoesNotMatch() {
    assertNull(ArbitraryInstances.get(ParentClassHasConstant.class));
  }
  public void testGet_nonPublicConstantNotUsed() {
    assertNull(ArbitraryInstances.get(NonPublicConstantIgnored.class));
  }
  public void testGet_nonStaticFieldNotUsed() {
    assertNull(ArbitraryInstances.get(NonStaticFieldIgnored.class));
  }
  public void testGet_constructorPreferredOverConstants() {
    assertNotNull(ArbitraryInstances.get(WithPublicConstructorAndConstant.class));
    assertTrue(
        ArbitraryInstances.get(WithPublicConstructorAndConstant.class)
            != ArbitraryInstances.get(WithPublicConstructorAndConstant.class));
  }