How to use

suggestUniqueVariableName

method

in

com.intellij.psi.codeStyle.JavaCodeStyleManager

/**
 * Suggests a unique name for the variable used at the specified location.
 *
 * @param baseNameInfo the base name info for the variable.
 * @param place        the location where the variable will be used.
 * @param lookForward  if true, the existing variables are searched in both directions; if false - only backward
 * @return the generated unique name
 */
@NotNull
public SuggestedNameInfo suggestUniqueVariableName(@NotNull SuggestedNameInfo baseNameInfo,
                              PsiElement place,
                              boolean lookForward) {
 return suggestUniqueVariableName(baseNameInfo, place, false, lookForward);
}

try {
 final Project project = operand.getProject();
 final String uniqueVariableName = JavaCodeStyleManager.getInstance(project).suggestUniqueVariableName("l", parent, false);
 final PsiDeclarationStatement declarationStatement =
  (PsiDeclarationStatement)JavaPsiFacade.getElementFactory(project).createStatementFromText(