oauth2/oauth2-jose/src/main/java/org/springframework/security/oauth2/jwt/ReactiveJwtDecoders.java
public static ReactiveJwtDecoder fromOidcIssuerLocation(String oidcIssuerLocation) {
		Map<String, Object> openidConfiguration = getOpenidConfiguration(oidcIssuerLocation);
		String metadataIssuer = "(unavailable)";
		if (openidConfiguration.containsKey("issuer")) {
			metadataIssuer = openidConfiguration.get("issuer").toString();
		}
		if (!oidcIssuerLocation.equals(metadataIssuer)) {
			throw new IllegalStateException("The Issuer \"" + metadataIssuer + "\" provided in the OpenID Configuration " +
					"did not match the requested issuer \"" + oidcIssuerLocation + "\"");
		}

		OAuth2TokenValidator<Jwt> jwtValidator =
				JwtValidators.createDefaultWithIssuer(oidcIssuerLocation);

		NimbusReactiveJwtDecoder jwtDecoder =
				new NimbusReactiveJwtDecoder(openidConfiguration.get("jwks_uri").toString());
		jwtDecoder.setJwtValidator(jwtValidator);

		return jwtDecoder;
	}
public static ReactiveJwtDecoder fromOidcIssuerLocation(String oidcIssuerLocation) {
		Map<String, Object> openidConfiguration = getOpenidConfiguration(oidcIssuerLocation);
		String metadataIssuer = "(unavailable)";
		if (openidConfiguration.containsKey("issuer")) {
			metadataIssuer = openidConfiguration.get("issuer").toString();
		}
		if (!oidcIssuerLocation.equals(metadataIssuer)) {
			throw new IllegalStateException("The Issuer \"" + metadataIssuer + "\" provided in the OpenID Configuration " +
					"did not match the requested issuer \"" + oidcIssuerLocation + "\"");
		}

		OAuth2TokenValidator<Jwt> jwtValidator =
				JwtValidators.createDefaultWithIssuer(oidcIssuerLocation);

		NimbusReactiveJwtDecoder jwtDecoder =
				new NimbusReactiveJwtDecoder(openidConfiguration.get("jwks_uri").toString());
		jwtDecoder.setJwtValidator(jwtValidator);

		return jwtDecoder;
	}
Creates a {@link ReactiveJwtDecoder} using the provided
<a href="https://openid.net/specs/openid-connect-core-1_0.html#IssuerIdentifier">Issuer</a> by making an
<a href="https://openid.net/specs/openid-connect-discovery-1_0.html#ProviderConfigurationRequest">OpenID Provider
Configuration Request</a> and using the values in the
<a href="https://openid.net/specs/openid-connect-discovery-1_0.html#ProviderConfigurationResponse">OpenID
Provider Configuration Response</a> to initialize the {@link ReactiveJwtDecoder}.

@param oidcIssuerLocation the <a href="https://openid.net/specs/openid-connect-core-1_0.html#IssuerIdentifier">Issuer</a>
@return a {@link ReactiveJwtDecoder} that was initialized by the OpenID Provider Configuration.