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CWE-576: EJB Bad Practices: Use of Java I/O

Weakness ID: 576
Abstraction: Variant
Status: Draft
Presentation Filter:
+ Description

Description Summary

The program violates the Enterprise JavaBeans (EJB) specification by using the package.

Extended Description

The Enterprise JavaBeans specification requires that every bean provider follow a set of programming guidelines designed to ensure that the bean will be portable and behave consistently in any EJB container. In this case, the program violates the following EJB guideline: "An enterprise bean must not use the package to attempt to access files and directories in the file system." The specification justifies this requirement in the following way: "The file system APIs are not well-suited for business components to access data. Business components should use a resource manager API, such as JDBC, to store data."

+ Time of Introduction
  • Architecture and Design
  • Implementation
+ Applicable Platforms



+ Common Consequences

Technical Impact: Quality degradation

+ Demonstrative Examples

Example 1

The following Java example is a simple stateless Enterprise JavaBean that retrieves the interest rate for the number of points for a mortgage. In this example, the interest rates for various points are retrieved from an XML document on the local file system, and the EJB uses the Java I/O API to retrieve the XML document from the local file system.

(Bad Code)
Example Language: Java 
public class InterestRateBean implements InterestRateRemote {

private Document interestRateXMLDocument = null;
private File interestRateFile = null;

public InterestRateBean() {
try {
/* get XML document from the local filesystem */
interestRateFile = new File(Constants.INTEREST_RATE_FILE);

if (interestRateFile.exists())
DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
DocumentBuilder db = dbf.newDocumentBuilder();
interestRateXMLDocument = db.parse(interestRateFile);
} catch (IOException ex) {...}

public BigDecimal getInterestRate(Integer points) {
return getInterestRateFromXML(points);

/* member function to retrieve interest rate from XML document on the local file system */
private BigDecimal getInterestRateFromXML(Integer points) {...}

This use of the Java I/O API within any kind of Enterprise JavaBean violates the EJB specification by using the package for accessing files within the local filesystem.

An Enterprise JavaBean should use a resource manager API for storing and accessing data. In the following example, the private member function getInterestRateFromXMLParser uses an XML parser API to retrieve the interest rates.

(Good Code)
Example Language: Java 
public class InterestRateBean implements InterestRateRemote {

public InterestRateBean() {

public BigDecimal getInterestRate(Integer points) {
return getInterestRateFromXMLParser(points);

/* member function to retrieve interest rate from XML document using an XML parser API */
private BigDecimal getInterestRateFromXMLParser(Integer points) {...}
+ Potential Mitigations

Phase: Implementation

Do not use Java I/O when writing EJBs.

+ Relationships
NatureTypeIDNameView(s) this relationship pertains toView(s)
ChildOfWeakness BaseWeakness Base695Use of Low-Level Functionality
Development Concepts (primary)699
Research Concepts (primary)1000
ChildOfCategoryCategory1001SFP Secondary Cluster: Use of an Improper API
Software Fault Pattern (SFP) Clusters (primary)888
+ Taxonomy Mappings
Mapped Taxonomy NameNode IDFitMapped Node Name
Software Fault PatternsSFP3Use of an improper API
+ Content History
Modification DateModifierOrganizationSource
2008-07-01Eric DalciCigitalExternal
updated Potential_Mitigations, Time_of_Introduction
2008-09-08CWE Content TeamMITREInternal
updated Relationships, Other_Notes
2009-10-29CWE Content TeamMITREInternal
updated Description, Other_Notes
2009-12-28CWE Content TeamMITREInternal
updated Demonstrative_Examples
2011-06-01CWE Content TeamMITREInternal
updated Common_Consequences
2011-06-27CWE Content TeamMITREInternal
updated Common_Consequences
2012-05-11CWE Content TeamMITREInternal
updated Relationships
2012-10-30CWE Content TeamMITREInternal
updated Potential_Mitigations
2014-07-30CWE Content TeamMITREInternal
updated Relationships, Taxonomy_Mappings

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Page Last Updated: May 05, 2017