java lwjgl 2 shader error

Question

I'm trying to compile shaders in java lwjgl 2.9, and if I run my game, it cannot compile shaders. question is why shader doesn't reconize const keyword, if I remove const then it throws error float is not reconized or something like that.

ERROR: 0:24: 'const' : syntax error syntax error. Could not compile shader!

Shader codes

Terrain Vertex shader

#version 150

in vec3 position;
in vec2 textureCoordinates;
in vec3 normal;

out vec2 pass_textureCoordinates;
out vec3 surfaceNormal;
out vec3 toLightVector[4];
out vec3 toCameraVector;
out float visibility;
out vec4 shadowCoords;

uniform mat4 transformationMatrix;
uniform mat4 projectionMatrix;
uniform mat4 viewMatrix;
uniform vec3 lightPosition[4];

uniform mat4 toShadowMapSpace;

const float density = 0;
const float gradient = 5.0;
const float shadowDistance = 150.0
const float transitionDistance = 10.0;

uniform vec4 plane;

void main(void){

vec4 worldPosition = transformationMatrix * vec4(position,1.0);
shadowCoords = toShadowMapSpace * worldPosition;

gl_ClipDistance[0] = dot(worldPosition, plane);

vec4 positionRelativeToCam = viewMatrix * worldPosition;
gl_Position = projectionMatrix * positionRelativeToCam;
pass_textureCoordinates = textureCoordinates;

surfaceNormal = (transformationMatrix * vec4(normal,0.0)).xyz;
for(int i=0;i<4;i++){
    toLightVector[i] = lightPosition[i] - worldPosition.xyz;
}
toCameraVector = (inverse(viewMatrix) * vec4(0.0,0.0,0.0,1.0)).xyz - worldPosition.xyz;

float distance = length(positionRelativeToCam.xyz);
visibility = exp(-pow((distance*density),gradient));
visibility = clamp(visibility,0.0,1.0);

distance = distance - (shadowDistance - transitionDistance);
distance = distance / transitionDistance;
shadowCoords.w = clamp(1.0-distance, 0.0, 1.0);
}

Terrain fragment shader

#version 330

in vec2 textureCoords;

out vec4 out_colour;

uniform sampler2D modelTexture;

void main(void){

float alpha = texture(modelTexture, textureCoords).a;
if(alpha < 0.5){
 discard;
}

out_colour = vec4(1.0);

}

Answer 1

const float gradient = 5.0;
const float shadowDistance = 150.0
                                  ^ where's the semicolon?
const float transitionDistance = 10.0;