Question

I have the following code:

private String foo;

public void setFoo(String bar)
{
  foo = bar + "bin/";
}

I expect this code to concat bar and "bin/" using the overloaded '+' operator. And when I do this same code sample in the debugger it works fine. For some reason though foo is always just equal to bar and never has the "bin/" in it.

Actual code:

 private String execpath_;

  public void setMambaPath(String executable)
  {

    if (!(executable.endsWith("/")))
      executable = executable.concat("/");

    execpath_ = executable + "bin/";
  }

elsewhere where execpath_ = just excutable without the bin/:

StringBuilder cmd = getSshCommand_();
cmd.append(execpath_ + "mambaService");

I don’t use execpath_ anywhere else

Answer 1

String is immutable variable and does not contain methods that change the content of the String object itself. So you need to use concat() method.

Or second approach you can use StringBuilder

private String foo;

public void setFoo(String bar)
{
  StringBuilder builder = new StringBuilder();
  builder.append(bar + "bin/");
  foo = builder.toString();
}