jersey2-guice-impl/src/main/java/com/squarespace/jersey2/guice/JerseyGuiceUtils.java
private static synchronized boolean isProviderPresent() {
    
    if (!SPI_CHECKED) {
      SPI_CHECKED = true;
      
      ServiceLocatorGenerator generator = lookupSPI();
      if (generator instanceof GuiceServiceLocatorGeneratorStub) {
        SPI_PRESENT = true;
        
      }
      
      if (!SPI_PRESENT) {
        LOG.warn("It appears jersey2-guice-spi is either not present or in conflict with some other Jar: {}", generator);
      }
    }
    
    return SPI_PRESENT;
  }
private static synchronized boolean isProviderPresent() {
    
    if (!SPI_CHECKED) {
      SPI_CHECKED = true;
      
      ServiceLocatorGenerator generator = lookupSPI();
      if (generator instanceof GuiceServiceLocatorGeneratorStub) {
        SPI_PRESENT = true;
        
      }
      
      if (!SPI_PRESENT) {
        LOG.warn("It appears jersey2-guice-spi is either not present or in conflict with some other Jar: {}", generator);
      }
    }
    
    return SPI_PRESENT;
  }
Returns {@code true} if jersey2-guice SPI is present.