glGetUniformLocation returns -1 with struct objects

Hello,

I try to get a uniform location but it returns -1

/////////////////////////////// Shader code
struct LightSource
{
  vec4 position;
  vec4 diffuse;
};

uniform LightSource light;

////////////////////////////// Java code
int lightPositionLocation=gl.glGetUniformLocation(shaderProgramID, "light.position");
int lightDiffuseLocation=gl.glGetUniformLocation(shaderProgramID, "light.diffuse");

thanks

damned I forgot shader were optimized
my uniform was not used in my code