A DESCRIPTION OF THE REQUEST :
Since Java 1.4, java.lang.Exception have 2 new constructors:
public Exception(Throwable cause)
public Exception(String message, Throwable cause)

java.io.IOException (and subclasses) lacks those new constructors, thus preventing "usefull" subclassing.

JUSTIFICATION :
Catching nested exceptions are a usefull way to convey information in case of error. All exception (and error) classes from the JRE should include all 4 constructors.

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
the following constructors to be available:
public IOException()
public IOException(String s)
public IOException(Throwable cause)
public IOException(String message, Throwable cause)
ACTUAL -
The only available constructors are:
public IOException()
public IOException(String s)

CUSTOMER SUBMITTED WORKAROUND :
no workaround