oauth2/oauth2-client/src/main/java/org/springframework/security/oauth2/client/endpoint/DefaultClientCredentialsTokenResponseClient.java
public void setRequestEntityConverter(Converter<OAuth2ClientCredentialsGrantRequest, RequestEntity<?>> requestEntityConverter) {
		Assert.notNull(requestEntityConverter, "requestEntityConverter cannot be null");
		this.requestEntityConverter = requestEntityConverter;
	}
public void setRequestEntityConverter(Converter<OAuth2ClientCredentialsGrantRequest, RequestEntity<?>> requestEntityConverter) {
		Assert.notNull(requestEntityConverter, "requestEntityConverter cannot be null");
		this.requestEntityConverter = requestEntityConverter;
	}
Sets the {@link Converter} used for converting the {@link OAuth2ClientCredentialsGrantRequest}
to a {@link RequestEntity} representation of the OAuth 2.0 Access Token Request.

@param requestEntityConverter the {@link Converter} used for converting to a {@link RequestEntity} representation of the Access Token Request