Java implements wrapper libraries which make these system calls callable from a Java application. Making objects callable using the same syntax as functions is a fairly trivial business. The price behaviour of puttable bonds is the opposite of that of a callable bond. The price behaviour of a callable bond is the opposite of that of puttable bond. The largest market for callable bonds is that of issues from government sponsored entities. A straight bond that is neither callable nor putable is called a bullet bond. However, many municipal bonds are callable, and this adds substantial risks to the strategy. Similar issues arise for callable bonds in the American municipal, corporate, and government agency sectors. Most rules engines function as a callable library. SCIP is implemented as C callable library. A turbo warrant (or callable bull/bear contract) is a kind of stock option. In August 2015 systemd started providing a login shell, callable via machinectl shell. G'MIC is primarily a script language callable from a shell. The authorized capital stock shall be divided into paid-in shares and callable shares. The generic term callable unit is sometimes used.